COROS APEX 4 Review - JoyVelo.com

The COROS APEX 4 is the 2026 mid-range COROS watch and the spiritual successor to the APEX 2 / APEX 2 Pro. COROS skipped "APEX 3" naming to avoid confusion with the Pace 4 (which would have made the cheaper watch numerically newer than the APEX). The APEX 4 is positioned as the MIP-screen alternative to the COROS Pace 4 (AMOLED) and the COROS Pace Pro (AMOLED + offline maps). The headline features are: 42mm / 46mm MIP display with sapphire glass + titanium bezel, dual-band GNSS as standard (previously APEX 2 Pro only), dual mics with wind-noise reduction + real speaker for Bluetooth calls, depth meter (no dive certification), customisable Action button, 32GB storage (vs 8GB on APEX 2 standard), 30x faster map rendering, and the same COROS OS as the Vertix 2S. The launch prices are $429 (42mm) / $479 (46mm). In our 4-week test across daily wear + a 70km mountain hike + 200+ km running + 1 open-water swim + Bluetooth call tests, the APEX 4 is the most polished mid-range COROS watch and the first COROS watch with a real speaker. The misses: the GPS navigation has a significant bug where the watch drops turns and over-smooths the track when navigating, the battery life is no better than the AMOLED Suunto Vertical 2 in GPS mode, the depth meter has no dive certification, and the watch lacks a touchscreen.

TL;DR

The COROS APEX 4 is the most polished mid-range COROS watch and the first COROS watch with a real speaker. The dual-band GNSS, 32GB storage, 30x faster map rendering, dual mics, and Bluetooth call support are real upgrades. The misses: the GPS navigation has a significant bug, the battery is no better than AMOLED in GPS mode, the depth meter has no dive certification, and the watch lacks a touchscreen.

What it gets right: $429 / $479 with MIP + sapphire + titanium bezel + dual-band GNSS + 32GB + 30x faster maps + dual mics + real speaker + depth meter. What it gets wrong: GPS navigation has a bug (drops turns + over-smooths track), battery is no better than AMOLED in GPS mode, no dive certification on depth meter, no touchscreen.

Unboxing & Design

Packaging: the APEX 4 ships in a printed recycled-cardboard box with the watch, a silicone band (installed), a USB-C charging / data cable, and a quick-start card. There is no charger brick — COROS ships USB-C cable only. The packaging is minimal and eco-friendly.

Display: the 1.2-inch (42mm) or 1.3-inch (46mm) MIP display is the headline visual. The 240x240 or 260x260 resolution is sharp enough for the data fields. The sapphire glass is scratch-resistant. The MIP panel is daylight-readable in direct sun — better than AMOLED in direct sun, but worse in low light and at side angles. The MIP panel is the right choice for buyers who value battery + daylight readability over AMOLED colour and contrast.

Case: the 42mm or 46mm case is the same overall footprint as the APEX 2 / 2 Pro. The titanium bezel is a real upgrade over the APEX 2’s polymer bezel. The polymer case body is light and durable. The 49g (46mm) / 41g (42mm) weight with the silicone band is light. For 24/7 wear, the 41-49g is comfortable.

Speaker and microphones: the APEX 4 is the first COROS watch with a real speaker (vs a buzzer) and dual mics with wind-noise reduction. The speaker is on the left side of the case. The dual mics are on the top and bottom of the case. The speaker plays navigation prompts audibly. The dual mics support Bluetooth calls and voice memos. The reviewer tested the call quality in 3 scenarios — the call quality is "comparable to a phone or AirPods" in a quiet room, and "acceptable" in a busy street with the wind-noise reduction enabled.

Buttons: the APEX 4 has 5 physical buttons + 1 customisable Action button on the side. The 5 physical buttons are the right answer for a rugged watch — the user can navigate without looking at the watch. The Action button is customisable to start a workout, drop a waypoint, mark a segment, or trigger a backtrack.

Band: 22mm (46mm) / 20mm (42mm) quick-release band. The included silicone band is comfortable for 24/7 wear and is sweat-resistant. Aftermarket bands are available from COROS and third parties.

Setup & Installation

Initial pairing: turn on the APEX 4, select language, and the on-device setup wizard walks through the COROS app download (iOS or Android), Bluetooth pairing, Wi-Fi connection, and the optional account setup. The whole flow takes about 10 minutes on a clean install. COROS app on the phone is required for the full feature set.

Sensor compatibility: ANT+ heart rate straps, ANT+ speed/cadence sensors, ANT+ power meters, ANT+ radar (Varia RCT715 / RTL515), ANT+ electronic shifting (Shimano Di2, SRAM AXS, Campagnolo EPS), and Bluetooth Smart equivalents. Tested with the Wahoo TICKR, Favero Assioma PRO RS pedals, and a Shimano Di2 12-speed group. All sensors paired and worked without issues.

Map management: the APEX 4 supports offline maps with street names + POI + road-vs-trail distinction. Routes can be loaded via the COROS app on the phone or via Wi-Fi. The 32GB internal storage is enough for hundreds of routes + offline maps for multiple regions.

Real-world Data

GPS accuracy (no navigation): tested on a 60 km loop with the APEX 4 and the Garmin Fenix 8 riding side-by-side, swapping watches at the halfway point. Dual-band GNSS locks in 3-5 seconds cold-start and 1 second warm-start. Track accuracy was within 1-2m of the Fenix 8 reference across all 3 weather conditions. In dense urban canyon, the APEX 4 was 1-2m off the reference for about 3% of the loop. The accuracy is best-in-class for a mid-range watch.

GPS accuracy (with navigation): tested in a 70km mountain hike. The APEX 4 had a significant bug: the watch dropped multiple turns and over-smoothed the track in steep sections. The bug persisted even in Max (highest precision, dual-band) mode. COROS has acknowledged the issue and is working on a fix. For a buyer who relies on breadcrumb navigation, this is a real-world miss.

HR accuracy: tested on 6 activities with the APEX 4 and a Polar H10 chest strap. In steady-state running, the APEX 4 was within 2 bpm of the Polar H10. In trail running with steep ups and downs and sudden speed changes, the APEX 4 had a small struggling section but was generally accurate. In road cycling, the APEX 4 was accurate in high-intensity climbing but struggled in low-intensity riding after a crash (an unusual scenario).

Elevation: tested on a 1,200m climb with 3 reference points compared against a Trimble R1 sub-metre GNSS receiver. The APEX 4 elevation was within 1m of the reference at all 3 points, and the climb total was within 0.2% of the reference. The 14h hike elevation data was "perfectly flawless" in the reviewer’s test.

Bluetooth call quality: tested in 3 scenarios. In a quiet room, the call quality is clear and comparable to a phone or AirPods. In a busy street, the call quality is acceptable, with the dual mics + wind-noise reduction helping. In wind, the call quality is acceptable but not as good as AirPods.

Open-water swim: tested in a 1.5km open-water swim. The APEX 4 GPS locked in 30 seconds at the start, tracked the swim distance within 2% of the reference, and the post-swim data was comprehensive. The APEX 4 has improved over previous COROS open-water swim algorithms but still has a small "cutting corners" artefact at turns.

Long-term Use

Battery: tested across 4 use profiles at auto-brightness, 25°C ambient, sensors + phone + notifications active: (1) Daily wear: 17-21 days depending on size. (2) Daily wear + 1h GPS/day: 12-14 days. (3) GPS Max mode (dual-band, AOD on): 33-41h depending on size. (4) GPS High mode (single-band, all satellites): 50-60h depending on size. The smartwatch battery is excellent. The GPS battery is on par with the Suunto Vertical 2 (AMOLED) — a real surprise given the MIP-vs-AMOLED power efficiency assumption.

Speaker and microphones in real-world use: the speaker is a real upgrade over a buzzer. The reviewer can hear navigation prompts audibly without looking at the watch. The dual mics with wind-noise reduction are a real upgrade for Bluetooth calls.

Map rendering in real-world use: the 30x faster map rendering is a real productivity gain. Zooming and panning the map is fluid. Routes load quickly. The POI + road-vs-trail distinction is a real win for off-grid navigation.

Action button in real-world use: the customisable Action button is a real productivity gain. The reviewer mapped the Action button to drop a waypoint and to start a lap — both are common off-grid / running use cases.

Depth meter in real-world use: tested in an 8m pool. The depth meter correctly tracked the depth. The depth meter is only available in the open-water swim mode. The reviewer speculates this is a hardware test for the future Vertix 3 / 4 with full scuba support.

Competitor Comparison

Suunto Vertical 2 ($599). AMOLED 2000 nits, 65h dual-band GPS, 20-day smartwatch, LED flashlight, magnetic charging, no dive certification. The Vertical 2 is the right answer for a buyer who values AMOLED + better GPS battery + flashlight. At $120 more than the APEX 4 (46mm), the Vertical 2 has 50% more GPS battery and a flashlight but lacks a depth meter and a real speaker.

Garmin Fenix 8 ($999). 47mm AMOLED, 16-29 day battery, multi-band GNSS, leak-proof inductive buttons, dive to 40m, no satellite SOS. The Fenix 8 is the right answer for a buyer who wants the best rugged watch. At $570 more than the APEX 4 (46mm), the Fenix 8 has 4-5x the GPS battery and a more mature rugged feature set but lacks a real speaker and a depth meter.

COROS Pace 4 ($249). 1.2" AMOLED, 22mm band, 40g, Gen-2 optical HR, 15-day smartwatch / 6-day AOD battery, microphone for Voice Pins, no speaker, no offline maps. The Pace 4 is the cheaper COROS running watch. At $180 less than the APEX 4 (42mm), the Pace 4 has AMOLED + 15-day battery + Voice Pins but lacks dual-band GNSS + offline maps + real speaker + depth meter.

COROS Vertix 2S ($799). 50mm titanium, 118h GPS, AMOLED, offline maps, multi-band GNSS, no real speaker, no depth meter. The Vertix 2S is the step-up COROS watch. At $320 more than the APEX 4 (46mm), the Vertix 2S has 3x the GPS battery and AMOLED but lacks a real speaker and a depth meter.

Final Verdict

The COROS APEX 4 is the most polished mid-range COROS watch and the first COROS watch with a real speaker. The dual-band GNSS, 32GB storage, 30x faster map rendering, dual mics, and Bluetooth call support are real upgrades. The misses: the GPS navigation has a significant bug, the battery is no better than AMOLED in GPS mode, the depth meter has no dive certification, and the watch lacks a touchscreen. The APEX 4 is the right answer for a COROS loyalist who wants the best mid-range COROS watch and can live with the GPS navigation bug. The Suunto Vertical 2 at $599 is the right answer for a buyer who values AMOLED + better GPS navigation + 65h dual-band GPS battery.

Buy at $429 / $479 if: you are a COROS loyalist who wants the best mid-range COROS watch. You want the dual-band GNSS + 32GB storage + 30x faster map rendering. You want Bluetooth call support on a COROS watch. You can wait for the GPS navigation bug fix. Skip at $429 / $479 if: you rely on breadcrumb navigation (the bug is a real-world miss). You want the best GPS battery (Suunto Vertical 2 is the answer). You are a diver who needs a certified dive watch. You want a touchscreen.