Apple Watch Series 12 and watchOS 27: Should You Upgrade or Sell Your Old Apple Watch?
Apple has just launched the Apple Watch Series 12 and Apple Watch Ultra 4, while watchOS 27 arrives on 14 September 2026. For owners of older Watches, however, the most important news may be the compatibility list: watchOS 27 supports Apple Watch Series 9 and later, Apple Watch SE 3, and Apple Watch Ultra 2 and later. That leaves several still-useful Watches outside Apple's newest major software release.
That does not suddenly make an Apple Watch Series 8, SE 2 or original Ultra worthless.
However, it does create a natural decision point.
Should you keep the Watch because it still does everything you need? Should you buy a newer refurbished model rather than a brand-new Series 12? Or, if the old Watch is already sitting unused, is now the time to sell it before another year of depreciation passes?
Sell My iPhone's current catalogue includes smartwatches alongside phones and tablets, with live listings for Apple Watch Series 6, Series 8, Series 9, Series 10, Series 11 and Ultra models.
Check what your Apple Watch could be worth on Sell My iPhone
Quick answer: If your Apple Watch still does everything you need, a new launch alone is not a reason to replace it. However, owners of Series 8 and older models should note that watchOS 27 no longer includes them on Apple's compatibility list. If you already intended to upgrade, checking the old Watch's value now makes more sense than leaving it unused for another year.
What did Apple announce in September 2026?
Apple introduced the Apple Watch Series 12 and Apple Watch Ultra 4 on 9 September 2026.
Both become available in the UK from 18 September.
Apple Watch Series 12 starts at £369, while Apple Watch Ultra 4 starts at £749.
Those launches arrive alongside watchOS 27, which becomes available on 14 September.
Apple Watch Series 12 focuses heavily on health and recovery
Apple says Series 12 introduces a new Health Sensing System and S11 chip.
Headline additions include:
- higher-frequency heart-rate measurements;
- more frequent HRV readings;
- a new readiness score;
- Siri AI through watchOS 27;
- new Audio Intelligence functions;
- expanded health and fitness features.
Apple describes its new sensor system as providing its most accurate heart-rate sensing in a wearable. That is Apple's own performance claim rather than an independent medical assessment.
For most buyers, though, the important question is not whether Series 12 has more sensors.
It is whether those additions improve something you actually care about.
What is new with Apple Watch Ultra 4?
Ultra 4 remains Apple's premium sports and outdoor model.
Apple says it adds:
- the same new Health Sensing System;
- S11 chip;
- readiness score;
- more frequent HRV readings;
- longer battery life;
- updated fitness capabilities;
- Siri AI through watchOS 27.
Apple quotes up to 45 hours of extended workout tracking and positions Ultra 4 as having the longest battery life of any Apple Watch to date.
For a runner, hiker or endurance athlete, that may be meaningful.
For someone who mainly checks notifications and closes activity rings, it may not justify spending £749.
Which Apple Watches support watchOS 27?
This may be the most important section for the second-hand market.
Apple's official compatibility list currently includes:
- Apple Watch Series 9
- Apple Watch Series 10
- Apple Watch Series 11
- Apple Watch Series 12
- Apple Watch SE 3
- Apple Watch Ultra 2
- Apple Watch Ultra 3
- Apple Watch Ultra 4
watchOS 27 requires a compatible iPhone running iOS 27 as well.
Which Apple Watches do not get watchOS 27?
Notably absent are:
- Apple Watch Series 8
- Apple Watch Series 7
- Apple Watch Series 6
- Apple Watch SE 2
- original Apple Watch Ultra
That is a substantial change because several of those Watches remain perfectly usable hardware.
It also creates a new search and resale question:
Does losing the latest watchOS release mean you should sell?
Not necessarily.
Does losing watchOS 27 support make an Apple Watch worthless?
No.
A Series 8 does not stop telling the time because Series 12 exists.
It can still perform many functions it handled previously.
However, the commercial position changes gradually.
Software support affects remaining useful life
Some buyers specifically want a Watch that will:
- receive Apple's latest features;
- remain current for longer;
- work with future app updates;
- receive current security and platform improvements.
A Series 9 now has a clear advantage over a Series 8 in that respect because it sits inside Apple's watchOS 27 support list.
That can influence refurbished buying decisions.
Price still matters
An unsupported Watch can remain a sensible purchase if it is cheap enough.
For example, somebody buying a low-cost Apple Watch primarily for:
- notifications;
- basic workouts;
- timers;
- activity tracking;
may be perfectly happy with an older model.
The mistake is paying nearly Series 9 money for much older hardware without understanding the software difference.
Apple Watch Series 8 vs Series 9: watchOS 27 creates a clearer gap
A year ago, the distinction between Series 8 and Series 9 might have felt relatively small to many ordinary users.
In September 2026, there is now one very obvious difference:
Series 9 gets watchOS 27. Series 8 does not.
Apple currently lists Series 9 among supported models, while its Series 8 compatibility has stopped at earlier versions of watchOS.
That matters to refurbished buyers
Imagine two watches:
Option A: Apple Watch Series 8 at £110
Option B: Apple Watch Series 9 at £140
Those are illustrative prices, not current Sell My iPhone buying offers.
Previously, the £30 saving might have made Series 8 an easy choice.
Now, someone planning to keep the Watch for several years may reasonably pay more for Series 9 because it remains inside Apple's current major-software cycle.
That does not mean Series 8 suddenly has no market.
It means the pricing gap needs to reflect the difference.
Is Apple Watch Series 9 still worth buying in 2026?
Potentially, yes — and watchOS 27 arguably makes it more interesting.
Series 9 is now several generations behind Series 12.
That normally means lower second-hand pricing.
However, Apple still includes it in watchOS 27.
That combination can be attractive:
- older purchase price;
- modern Apple Watch experience;
- current major software support.
Sell My iPhone's current homepage lists Apple Watch Series 9 41mm GPS at £90 and a 45mm GPS version at the same headline figure at the time of checking. Values vary by exact model and condition, so treat live quotes as temporary rather than permanent prices.
Check current smartwatch values on Sell My iPhone
What about Apple Watch Series 10?
Series 10 can occupy an even stronger refurbished middle ground.
It is newer than Series 9, remains compatible with watchOS 27 and may now become more available second-hand as Series 12 reaches shops.
Sell My iPhone currently lists a Series 10 46mm GPS + Cellular among its live devices.
Previous-generation does not mean obsolete
This is one of the central advantages of refurbished technology.
Series 12 may have the newest health hardware.
However, Series 10 still provides far more smartwatch capability than many owners actually need.
If the price difference is substantial, an older supported Watch can provide better value.
What about Apple Watch Series 11?
Series 11 is only one generation behind Series 12.
It also runs watchOS 27.
That means anyone upgrading from Series 11 should have a particularly clear reason.
Do not upgrade purely because the number changed
Consider what Series 12 gives you that Series 11 does not.
If the new Health Sensing System, readiness features or another specific capability matters to you, the upgrade may make sense.
If your Series 11 already:
- lasts through your day;
- tracks the workouts you need;
- handles notifications;
- remains in excellent condition;
keeping it could be far more financially sensible.
Sell My iPhone already shows Series 11 devices in its current catalogue, meaning owners who do decide to move on have an established trade-in route.
Is Apple Watch Ultra 2 now the refurbished sweet spot?
It could be for some buyers.
Ultra 4 starts at £749.
Meanwhile, Ultra 2 remains compatible with watchOS 27 and retains the rugged design and premium positioning of the Ultra family.
Sell My iPhone's homepage currently lists Apple Watch Ultra 2 49mm GPS + Cellular among its popular smartwatch devices.
Ultra buyers should compare needs, not model numbers
Ultra 4 adds newer health sensing and longer workout battery capabilities.
But an Ultra 2 may still offer more than enough for someone who wants:
- a larger screen;
- rugged titanium hardware;
- Cellular;
- strong GPS;
- longer battery life than a standard Watch;
- outdoor and sports features.
That creates a potentially attractive refurbished market.
Does the original Apple Watch Ultra still have value?
Potentially, yes.
However, original Ultra owners face a more interesting software question.
Apple's watchOS 27 list starts with Ultra 2, meaning the first-generation Ultra is not included.
That may influence future buyer demand.
It does not erase the substantial hardware value of the original Ultra overnight.
Yet someone comparing an original Ultra with an Ultra 2 now has another reason to favour the newer model.
Should you sell an Apple Watch before it loses software support?
There is no universal rule.
Trying to perfectly predict depreciation is difficult.
However, there is a sensible general principle:
once you already know you are going to replace the Watch, there is little benefit in leaving the old one unused for years.
Software-support transitions can matter
Series 8 provides a good example.
It was a relatively recent premium Watch.
Now, watchOS 27 has drawn a clearer line between it and Series 9.
Future software releases may create similar divisions between later generations.
That does not mean panic-selling.
It means understanding that software support is one component of resale value.
What actually determines Apple Watch resale value?
Model age matters, but it is only the starting point.
Several other factors can materially change the value of two identical-generation Watches.
Battery health
Rechargeable batteries degrade.
Apple lets owners check their Watch battery's Maximum Capacity by opening:
Settings → Battery → Battery Health
The percentage compares current battery capacity with when the battery was new.
That makes battery health one of the easiest factors to check before selling.
Case size
A 41mm Watch and a 45mm Watch are different products.
Later generations also use other size combinations.
Always identify the exact variant.
GPS or GPS + Cellular
Cellular versions are distinct models.
Do not select Cellular simply because it produces a better-looking quote.
Cosmetic condition
A Watch spends its life exposed on your wrist.
Typical wear includes:
- screen scratches;
- case marks;
- strap wear.
A heavily cracked display is very different from light surface wear.
Functional condition
Check:
- touchscreen;
- Digital Crown;
- side button;
- microphone;
- speaker;
- charging;
- sensors;
- Cellular where relevant.
A visually immaculate Watch with a failed Digital Crown is still faulty.
Does poor Apple Watch battery health reduce value?
It can.
Battery life has a direct effect on usability.
Apple itself explains that Watch batteries have a limited lifespan and may eventually require service.
A buyer comparing two identical Series 9 Watches may therefore prefer the one with stronger Maximum Capacity.
Do not confuse battery percentage with battery health
Seeing:
Battery: 100%
simply means the Watch is fully charged.
It does not mean the battery retains 100% of its original capacity.
Battery Health is the relevant screen.
Can Samsung Galaxy Watch owners check battery health too?
Yes, on supported models.
Samsung's UK support guidance says Galaxy Watch owners can use Samsung Members to run connected-device diagnostics.
Samsung says self-diagnosis supports the Watch4 series and later.
The process is:
- Open Samsung Members.
- Select Support.
- Choose Connected Device Diagnostics.
- Select Battery Status.
That makes battery condition relevant beyond Apple Watch.
Sell My iPhone's live site currently includes Samsung Galaxy Watch models too, including the Galaxy Watch 6.
What about Garmin watches?
Garmin occupies a different part of the smartwatch market.
Many Garmin buyers prioritise:
- running;
- cycling;
- GPS;
- training metrics;
- outdoor navigation;
- multi-day battery life.
Garmin's current 2026 range spans wellness watches such as Venu through specialist running, outdoor and golf models.
Sell My iPhone's own recent old-tech guide confirms that its smartwatch catalogue includes Garmin alongside Apple and Samsung.
Garmin ownership transfer works differently
Garmin says its wearable devices can generally be used by a new owner without requiring action from the previous owner.
However, Garmin recommends that sellers perform a factory reset to remove personal data and settings.
It also recommends buyers check for a valid serial number and, where possible, original proof of purchase for warranty purposes.
That is useful advice for any second-hand Garmin purchase.
Should you sell an older Galaxy Watch after Samsung launches a new one?
The same logic applies as Apple Watch.
Samsung continues to push Galaxy Watch further into health and AI features.
In July 2026, Samsung specifically described its next-generation Watch direction around AI-driven health insights, enhanced battery life and updated internal components.
That does not make a Galaxy Watch 6 useless.
In fact, Sell My iPhone currently still lists Galaxy Watch 6 among popular smartwatch products.
Upgrade only when the difference matters
Ask:
- Is battery life becoming poor?
- Does the new Watch offer a feature I will use?
- Is software support becoming an issue?
- Is my current Watch damaged?
- Have I simply stopped wearing it?
If the Watch is still meeting your needs, keeping it costs nothing.
If it is sitting unused, that is a different calculation.
Why unused smartwatches lose value quickly
Smartwatches combine several types of depreciation.
Hardware gets older
Newer generations appear annually or close to annually.
Batteries age
Rechargeable batteries do not improve in storage.
Software moves forward
watchOS 27 demonstrates how a previously current Watch can fall outside the newest software generation.
More used stock enters the market
When Apple launches Series 12, some Series 11 owners upgrade.
Some Series 10 owners upgrade.
Some Ultra owners move to Ultra 4.
That can increase the number of older Watches available second-hand.
Therefore, if yours is already redundant, keeping it in a drawer is unlikely to improve its value.
Sell My iPhone's guide to unused technology makes the same broader point: smartwatches are one of the common categories that can remain commercially useful even after the original owner stops using them.
Read: What to Do With Old Tech in 2026
Do you need the Apple Watch box to sell it?
For Sell My iPhone, the original box is not the key requirement.
However, its current preparation guidance specifically says smartwatches should include their charger and strap.
That is worth knowing before you create a trade-in and then discover the charger disappeared during your last house move.
Find these first
Before selling, locate:
- Watch;
- compatible charger;
- strap.
Then identify the exact model and condition.
Read Sell My iPhone's device preparation guide
How do you identify your exact Apple Watch?
Do not submit:
"Apple Watch Series 9"
if you have not checked the size and connectivity version.
An exact model could instead be:
Apple Watch Series 9 45mm GPS
or:
Apple Watch Series 9 GPS + Cellular
These are different products.
Check the Watch app and device information
Apple provides model-identification information through its support resources.
Before requesting a valuation, confirm:
- generation;
- case size;
- GPS or Cellular;
- case material where relevant.
This reduces the risk of selecting the wrong product.
How do you prepare an Apple Watch for sale?
Do not simply erase the screen and post it.
The account relationship matters.
Unpair the Watch properly
Apple Watch uses Activation Lock through Find My.
Sell My iPhone already has a dedicated guide explaining how to unpair an Apple Watch before selling.
When you still have the paired iPhone, unpairing through the Watch app is usually the cleanest route.
Why does unpairing matter?
It:
- separates the Watch from the iPhone;
- removes personal data;
- deals with Activation Lock when completed correctly;
- makes the device usable by its next owner.
A Watch that remains tied to your Apple Account can create unnecessary delays.
What if you no longer have the paired iPhone?
Apple provides methods for dealing with Watch account removal even when the original iPhone is unavailable.
However, simply erasing the Watch itself does not always address the account relationship in the same way.
If you are the legitimate owner, follow Apple's current account-removal process before passing the Watch on.
Sell My iPhone's existing Apple Watch unpairing guide also explains the alternative route.
Should you replace the battery before selling an Apple Watch?
Not automatically.
This is an economic decision.
Imagine:
- the Watch in its current state is worth £80;
- battery service costs £95;
- the repaired Watch is worth £120.
Spending £95 to gain £40 of value would not make financial sense.
Those figures are purely illustrative.
The principle is what matters.
Check the as-is value first
Before paying for a repair:
- identify the exact Watch;
- check battery health;
- get a current resale estimate;
- check service cost;
- compare the likely improvement in resale value.
Repair only if the numbers work.
Does a cracked Apple Watch screen still have value?
Potentially.
A cracked display obviously reduces condition.
However, whether the Watch becomes economically worthless depends on the model.
A relatively recent premium Watch may retain parts or refurbishment value despite damage.
A much older model with several faults may not.
Sell My iPhone's smartwatch product pages include a Faulty condition alongside better grades, indicating that non-perfect smartwatches can still enter its valuation process.
Check Sell My iPhone's current FAQs
What are older Apple Watches worth right now?
Values change constantly, so this is not a permanent price list.
However, the live Sell My iPhone homepage currently illustrates how widely values can differ.
At the time of checking, headline listings included examples such as:
- Apple Watch Series 6 40mm GPS — £25
- Apple Watch Series 9 41mm GPS — £90
- Apple Watch Series 10 46mm GPS + Cellular — £145
- Apple Watch Ultra 2 49mm GPS + Cellular — £230
- Apple Watch Ultra 3 49mm GPS + Cellular — £363
These are live site examples rather than guaranteed values for every condition or configuration.
Why the differences are useful
They demonstrate something important.
An "old smartwatch" is not one market.
Generation, specification and model tier matter enormously.
That is why searching the exact Watch is far better than assuming:
"Mine is a few years old, so it probably isn't worth anything."
Check the live value of your smartwatch
A practical example: upgrading from Series 8 to Series 12
Imagine you own a Series 8.
It still works well.
Battery Maximum Capacity is reasonable.
However, you like Series 12's new health and readiness features and have decided to upgrade.
Option one: keep both
You buy Series 12 and put Series 8 into a drawer as a backup.
That is sensible if you genuinely expect to use it.
Option two: give Series 8 to somebody
Another iPhone owner in your family may get years of useful life from it.
Option three: sell Series 8
You acknowledge that Series 8 is no longer on the watchOS 27 compatibility list.
You check the current trade-in value, unpair it properly and sell while the Watch is still functional.
Option four: wait three years
The Watch spends three years unused.
Its battery ages further.
More generations arrive.
Its software falls further behind.
If you already know you will never wear it again, Option Four offers little obvious financial advantage.
Another example: Ultra 2 versus Ultra 4
Suppose you own Ultra 2.
Ultra 4 launches at £749.
Apple has improved battery capability, health sensing and readiness functionality.
But Ultra 2 still supports watchOS 27.
Ask what you are actually buying
If the new features materially improve your training, the upgrade may be worthwhile.
If you simply want:
- large display;
- titanium body;
- strong GPS;
- Cellular;
- outdoor features;
Ultra 2 may still fulfil those needs perfectly.
Keeping it may be the smarter option.
This is exactly why new technology launches do not automatically mean old technology should be replaced.
Could Series 12 increase demand for refurbished Series 9 and 10?
Potentially.
A flagship launch can push consumers in two directions.
One group wants the newest model.
Another thinks:
"I like Apple Watch, but I do not need to spend £369."
That second group may then investigate previous generations.
Because Series 9 and Series 10 remain compatible with watchOS 27, they have a particularly clear argument as refurbished options.
This can help maintain a healthy resale market for supported older hardware.
What smartwatch should you buy refurbished in late 2026?
For Apple users, a simple framework works well.
Lowest-cost Apple Watch
Consider older models if price matters most, but understand the software-support trade-off.
Best balance of price and current software
Series 9 is particularly interesting because it remains on watchOS 27 while sitting several generations behind Series 12.
Newer refurbished choice
Series 10 or Series 11 may offer younger batteries and newer hardware while still costing less than a new Series 12 depending on the seller.
Premium outdoor choice
Ultra 2 deserves attention because it remains supported by watchOS 27 while Ultra 4 now occupies the newest £749 position.
The actual best choice still depends on price and condition.
What about Samsung and Garmin sellers?
Do not assume Sell My iPhone only buys Apple wearables.
Its recent old-tech guide explicitly says the catalogue contains smartwatches from Apple, Samsung and Garmin.
The live homepage also currently shows Samsung Galaxy Watch models.
So if you moved:
- from Galaxy Watch to Apple Watch;
- from Apple Watch to Garmin;
- from Garmin to Galaxy Watch;
- or simply stopped wearing a smartwatch;
check the old device rather than forgetting about it.
Search Sell My iPhone for your smartwatch
The key takeaway
Apple's September 2026 launch matters to the refurbished smartwatch market for two reasons.
First, Apple Watch Series 12 and Ultra 4 create a new upgrade cycle.
Second, watchOS 27 creates a new software-support boundary.
Series 9 and later remain supported in the mainstream Series range.
Ultra 2 and later remain supported in the Ultra range.
Series 8, original Ultra and several older Watches now sit outside Apple's newest major watchOS release.
That does not make them useless.
However, if you already intended to upgrade, now is a sensible time to check their remaining value.
Before selling:
- confirm the exact model;
- check the case size;
- confirm GPS or Cellular;
- check battery health;
- test the display and controls;
- unpair the Watch;
- remove Activation Lock;
- find the charger and strap;
- select the condition honestly.
If you still use the Watch every day, keep it.
If you have replaced it and it has already become drawer technology, checking its value is far more useful than assuming it is worthless.
Check what your old smartwatch could be worth with Sell My iPhone
Frequently asked questions
Apple Watch Series 12 and watchOS 27
When does Apple Watch Series 12 come out in the UK?
Apple Watch Series 12 becomes available in the UK on 18 September 2026 and starts at £369.
How much does Apple Watch Ultra 4 cost in the UK?
Apple Watch Ultra 4 starts at £749 and becomes available on 18 September 2026.
Which Apple Watches support watchOS 27?
Apple lists Series 9, 10, 11 and 12, Apple Watch SE 3, and Apple Watch Ultra 2, Ultra 3 and Ultra 4.
Does Apple Watch Series 8 get watchOS 27?
No. Series 8 is not on Apple's watchOS 27 compatibility list. However, that does not stop an existing Series 8 from continuing to function with the software it already supports.
Selling an older Apple Watch
Is Apple Watch Series 8 still worth anything?
Potentially, yes. Sell My iPhone currently has a live Series 8 smartwatch valuation page with condition levels including New, Very Good, Average, Poor and Faulty.
Check your current Apple Watch value
Does Apple Watch battery health affect resale value?
It can. Battery capacity affects how long the Watch lasts between charges. Apple lets users check Maximum Capacity under Settings → Battery → Battery Health.
Do I need to unpair my Apple Watch before selling it?
Yes. Properly unpair the Watch and deal with Activation Lock before handing it over.
Read Sell My iPhone's Apple Watch unpairing guide
Do I need the charger and strap when selling my smartwatch?
Sell My iPhone's current preparation guidance specifically asks smartwatch sellers to include the charger and strap.
Samsung and Garmin
Can I sell a Samsung Galaxy Watch to Sell My iPhone?
Potentially, yes. The live site currently displays Samsung Galaxy Watch models among its popular smartwatches.
Does Sell My iPhone buy Garmin watches?
Its current old-tech guide says the smartwatch catalogue includes Garmin devices as well as Apple and Samsung.
Sources and further reading
Apple Newsroom — Introducing Apple Watch Series 12
Apple Newsroom — Introducing Apple Watch Ultra 4
Apple Support — Apple Watch Battery Health
Samsung UK — Galaxy Watch Battery Diagnostics
Garmin — Buying, Selling or Giving Away a Garmin Wearable
Sell My iPhone — Check Your Device Value
Sell My iPhone — Frequently Asked Questions
Sell My iPhone — Prepare Your Device for Sale
Sell My iPhone — How to Unpair Your Apple Watch Ready to Sell