COROS APEX 4 Review: GPS, Maps and Ultra Battery 2025

Long battery life, with a navigation caveat

Image: official product image from coros.com

Is the COROS APEX 4 good for ultrarunning?

Mostly. The COROS APEX 4 is a good ultrarunning watch if long battery life, offline maps and training tools matter more than smartwatch apps or an AMOLED screen. The 46 mm model is rated for up to 65 hours in GPS endurance mode, but one mountain test raised a concern about GPS tracking during route navigation.

Key facts

Category	GPS watches
Release	Launched and on sale 15 October 2025
Price	$429 (42 mm), $479 (46 mm); €429 (42 mm), €469 (46 mm); £429; C$589
Key specs	42 mm and 46 mm sizes MIP display with sapphire glass and titanium bezel Dual-frequency GPS and offline maps Battery life: up to 65 hours GPS endurance mode on the 46 mm model; 42 mm has shorter GPS life Speaker and microphone, including calls when paired with a nearby phone
Best for	Ultrarunners and mountain runners who value long GPS battery life, offline maps and training features more than smartwatch apps or an AMOLED display.
Consensus score	8.0 out of 10

What is the COROS APEX 4?

Released in October 2025, the COROS APEX 4 is a training-focused outdoor watch available in 42 mm and 46 mm sizes. It combines a MIP display with sapphire glass and a titanium bezel, plus dual-frequency GPS and offline maps. Reviewers at Hodinky-365 describe a comfortable fit for running, while testers also highlight its training tools and detailed mapping. The display is designed for outdoor readability, though it is less vivid than AMOLED. The APEX 4 adds a speaker and microphone, with calls available when paired to a nearby phone.

How does it perform on ultras?

Battery life is a key strength for long races: COROS rates the 46 mm model for up to 65 hours in GPS endurance mode, while the 42 mm version has less GPS runtime. Several reviewers found GPS tracking accurate, but DC Rainmaker reported substantial errors on a mountain hike with route navigation enabled. COROS later said it had fixed the issue, but the reviewer had not retested it. Maps are useful for navigation, although testers note they can be difficult to see in low light. That makes the COROS APEX 4 a capable option with a navigation caveat.

Who should buy the APEX 4?

The APEX 4 suits ultrarunners and mountain runners who prioritise battery life, offline mapping and training features. Choose the 46 mm model if you want the stated maximum of 65 hours in GPS endurance mode; consider the 42 mm if a smaller case matters more and its shorter GPS life fits your needs. Its sapphire glass and titanium bezel offer a durable build, but the MIP screen is less vivid than AMOLED. Reviewers also note limited smartwatch features, including no contactless payments or broad third-party app ecosystem.

What reviewers agree on

Strengths

Long GPS battery life, especially on the 46 mm model
Offline maps with useful navigation features
Generally accurate GPS and training metrics in several reviews
Durable titanium bezel and sapphire glass
Speaker and microphone add useful call and voice functions

Weaknesses

GPS tracking with route navigation was poor in one mountain-hike test; a reported fix was not independently retested
MIP display is dimmer than AMOLED and maps can be difficult to see in low light
The 42 mm model has shorter GPS battery life
No contactless payments or deep third-party app ecosystem
Speaker may not work well after swimming, and calls depend on a nearby paired phone

Frequently asked questions

Which COROS APEX 4 size should I choose?

The COROS APEX 4 comes in 42 mm and 46 mm sizes, and reviewers describe it as comfortable for running. The 46 mm model has the longer stated GPS runtime, up to 65 hours in endurance mode. The 42 mm has shorter GPS life, so choose based on fit and the tracking time you need.

How long does the COROS APEX 4 battery last, and is it durable?

COROS rates the 46 mm APEX 4 for up to 65 hours in GPS endurance mode; the 42 mm version has less GPS runtime. The watch has sapphire glass and a titanium bezel, and is rated for 50 m water resistance. The stated endurance figure applies to GPS endurance mode.

Is the COROS APEX 4 better than an AMOLED GPS watch?

That depends on your priorities. The APEX 4 uses a MIP display that reviewers say is readable outdoors, but less vivid than AMOLED, and its maps can be hard to see in low light. It offers offline maps and long GPS battery life, especially in the 46 mm model, while smartwatch features remain limited.

Sources behind this review

How this review works: the consensus score of 8.0 out of 10 condenses the verdicts of the independent reviews and lab tests listed above, compiled by endurance coach Paul Forrest. Prices and specifications are those quoted by reviewers at the time of testing and may have changed.

Training for an ultra? See endurance coaching with Paul Forrest.