OceanMAP
Manual Sites FAQ App Store · Coming Soon KO EN Watch Intro →
PATENT PENDING

APPLE WATCH ULTRA Underwater navigation.

No extra hardware·No subscription·Underwater nav on your wrist.

A complete real-time underwater navigation system that runs on your Apple Watch Ultra. Dual-band GPS on the surface, sensor fusion (magnetometer · pressure · IMU) underwater — bearing and distance never drop.

Watch the Intro→ 📘 User Manual→ How it works↓
App Store · Coming Soon
One-time purchase · No subscription Planned $89.99
Apple Watch Ultra iPhone iCloud Sync EN · KO · JA · ZH
Ocean MAP A→B compass navigation screen
DeviceApple Watch Ultra
Depth100m WR · 0.1m
GPSL1 + L5Dual band
SensorsMag · Pressure · IMU
StatusComing Soon
Intro Video

60 seconds is all it takes.
See how it works underwater.

Why Ocean MAP

No extra gear. No monthly fees.
It already runs on your wrist.

01Hardware

No extra hardware.

No receiver, display or dedicated unit to buy. The Apple Watch Ultra already on your wrist is your nav computer, compass and map.

HARDWAREApple Watch Ultra
02Cost

No subscription.

No monthly or annual fees. One purchase covers every navigation feature and the logbook for life. Sync happens through your own iCloud account.

BILLINGOne-time · Lifetime
03Built-in

Depth & safety
info built in.

Depth, dive time, NDL and ascent rate sit right on the navigation screen — supplemental safety info from a certified depth sensor.

SAFETY INFOBuilt-in
ADAPTIVE NAVIGATION

It gets more accurate the more you dive.
It evolves to fit your diving.

Divers don't hold still — you wave, you signal, and every diver's kick is different. Ocean MAP reads that motion and recalibrates to you on every dive.

Diver profile — fins, style and learned stride
01Posture

Steady bearing,
even when you move.

Gyroscope and gravity sensors tell a deliberate compass sighting from hand motion, and gyro and magnetometer cross-check in real time so a twisted wrist never lets heading error accumulate. Distance advances only on each fin kick, so your position never drifts while you hold still. Sight steady and you get a confirmed, accurate reading.

STABILIZESensor-fusion
02Self-calibration

Distance sharpens
dive after dive.

On surfacing, the GPS entry↔exit displacement is compared with the underwater track to learn your fin-kick stride. Distance estimates converge to you over dives — all on-device.

GPS SELF-CALIBRATIONOn-device
03Profile

Starts tuned to
your fins and style.

Fin type and dive style (relaxed · balanced · aggressive) set your initial stride, and kick patterns auto-detect your style — so you start close to your true value from dive one.

DIVER PROFILEPersonalized
Depth & Safety · BUILT-IN

Depth through NDL,
all on one screen.

Depth and safety info screen

Logging starts
the moment you descend.

The pressure sensor measures depth in 0.1m increments. Auto-detection picks up dive start and end with no manual input. NDL, ascent rate and water temperature are computed in real time — no setup required.

Current Depth
3.9m
NDL
60min
Ascent Rate
0.0m/min
Temperature
14°C
DIGITAL LOGBOOK · iPhone

After the dive,
everything organizes itself on iPhone.

Dives auto-logged on the Watch sync via iCloud and open up as logbook entries, a site map and statistics on iPhone. CSV export and notes are not paid extras.

iPhone · 01HOME

Home — dive summary

Total dives, max depth and accumulated time as cards. Recent dives sorted chronologically.

iPhone log home screen
iPhone · 02SITES

Site map

Entry points captured automatically; points of interest marked manually. Coordinates and dates stored together.

iPhone dive site map screen
iPhone · 03DETAIL

Dive detail

Max and average depth, dive time, kick count and traveled distance on a single page.

iPhone dive detail screen
PatentPendingUnderwater navigation algorithm application in progress
AlgorithmEKF Sensor FusionMagnetometer · Pressure · IMU fused
AdaptivePersonal stride self-calibrationLearns from GPS ground truth each dive
GPSL1 + L5 dual bandHigh-precision entry-point marking
SynciCloud · Watch ↔ iPhoneThrough your own account
A CHART WE DRAW TOGETHER · OCEANMAP EARTH

Your dive
becomes a world map.

While Ocean MAP guides you safely underwater, your track — anonymously — joins a global underwater chart. The next diver enters that site already knowing it, incidents drop, and the whole diving industry grows together. 3,885 dive sites are already registered.

01

Navigate safely

Sensor fusion finds the way where GPS can't reach — underwater.

02

Track contributes anonymously

With your consent, route & entry point become a piece of the chart.

03

Next diver benefits

Understand a new site from the chart before you even enter.

04

The industry grows

Fewer incidents, lower barriers, more divers worldwide.

Explore the underwater chart → map.oceanmap.co.kr
DIVE SITES · WORKS WORLDWIDE

Wherever divers go, it works.

Strong currents, deep wrecks, atoll mazes — sensor fusion adapts to the navigation challenge each site presents.

PHILIPPINES

Cebu · Moalboal Sardine run · Pescador wall

Sardine-run drift dives and Pescador Island walls. Mark the entry, track drift distance in real time, return to the boat with confidence.

driftwallA→B
PHILIPPINES

Bohol · Balicasag Jack tornadoes

Jackfish tornadoes and steep wall dives. At depth the magnetometer holds your bearing back to the entry point even as the wall drops away.

wallpelagicbearing
INDONESIA

Bali · Tulamben USS Liberty wreck

The USS Liberty wreck and coral garden. At 30m on the hull, glance at your wrist for the exit heading and ascend along the safest route.

wreckshallowexit nav
INDONESIA

Nusa Penida Manta Point · Crystal Bay

Manta Point and Crystal Bay drifts. Cumulative travel distance during the drift estimates the recall distance for the boat.

driftmantadistance
JAPAN

Okinawa · Kerama Coral maze

Narrow channels through coral mazes. GPS remembers your entry coordinates, and after ascent the watch points you back to the boat.

coralshallowreturn
THAILAND

Similan Islands White Rock · Elephant Head

Strong-current dive sites at White Rock and Elephant Head Rock. The EKF estimates surface-recovery distance after a drift dive ends.

driftstrong currentEKF
PALAU

Palau · Blue Corner Sharks and mantas

Corner dive with sharks and mantas in heavy current. IMU compensates for posture shifts so the bearing stays stable when the flow grabs you.

sharkcornerIMU comp
MALDIVES

Ari Atoll Channel drifts · Manta points

Channel drifts and manta cleaning stations between atolls. Even when the boat falls out of sight, GPS marking and magnetic navigation bring you home.

atolldriftboat return
EGYPT

Red Sea · Safaga Salem Express · Salama

Liveaboard wreck dives at Salem Express and Salama. Vertical navigation and deck-by-deck position tracking are the difference between safe and lost.

wreckliveaboardvertical nav
AUSTRALIA

Great Barrier Reef Cairns

A reef complex large enough to get genuinely lost in. Map the site and pin your entry by GPS — finding a safe ascent point becomes a glance, not a guess.

reeflarge areasite map
ECUADOR

Galápagos · Darwin / Wolf Whale shark · hammerhead

Pelagic sites for whale sharks and hammerheads. Aggressive current and low visibility demand a fused bearing you can trust through every gust.

pelagicwhale sharkEKF
KOREA

Jeju · Gapado Korean home waters

Home sites for Korean divers. Korean language UI, KST timestamps, and a built-in database of domestic dive locations.

Koreahome base한국어

The sites above are illustrative. Ocean MAP is sensor-based, not location-based — it works at any dive site where magnetic field and pressure can be measured.

APP STORE · COMING SOON

Coming soon
to your wrist.

Ocean MAP is getting ready for its App Store launch. Dual-band GPS on the surface, magnetometer · pressure · IMU sensor fusion underwater — a true real-time underwater navigation system, with depth and NDL shown as supplemental safety info from a certified depth sensor, all on a single watch.

Planned price · One-time
$89.99 No subscription
One-time purchase · Lifetime use · No extra hardware
NEXT · INSTAGRAM
Get launch news first
Launch dates, new dive sites and real-world test footage drop on Instagram first.
Follow @oceanmap4

⚠ Ocean MAP is a supplemental dive tool. Depth, NDL and ascent-rate readings are for reference only and are not a substitute for a certified dive computer. Always dive with certified equipment.

FREQUENTLY ASKED · FAQ

Before launch.

The questions divers ask most often.

Q1Is this a replacement for a certified dive computer?

No. Ocean MAP is a supplemental tool and is not certified to EN 13319 or equivalent standards.

Always wear a certified dive computer alongside Ocean MAP. Our NDL, ascent rate and depth readings are for reference only — they cannot serve as the final basis for dive planning or decompression decisions.

Right now we focus on polishing the navigation (compass · map tracking) features. Dive-computer certification is on the post-launch roadmap.

Q2Do I need Apple Watch Ultra specifically? Will a regular Apple Watch work?

Yes — Ocean MAP requires Apple Watch Ultra (1, 2 or 3). It will not run on standard Apple Watch (Series 9 / 10, etc.).

Three hardware requirements drive this:

  • 100m water resistance — only Apple Watch Ultra is certified for diving (EN 13319 case)
  • Dual-band GPS (L1+L5) — required to mark your entry point within ~1m accuracy
  • Action button + larger display — essential for marking and confirmation under gloves and low-visibility
Q3GPS doesn't work underwater. How do you track position?

Right before descent, GPS captures your entry coordinates on the surface. Underwater, three sensors estimate position:

  • Magnetometer — real-time bearing (true / magnetic north)
  • Pressure sensor — depth in 0.1m increments
  • IMU (accelerometer + gyroscope) — distance traveled from fin-kick detection

An Extended Kalman Filter (EKF) fuses all three so each sensor's weakness (magnetometer near metal, IMU drift over time, pressure affected by current) is corrected by the others. The return distance and bearing to your entry point are computed by the same model.

Q4How accurate is it?

Field-test numbers (avg. of 10 × 20m dives):

  • Bearing error: ±2°
  • Distance error: ±8% (over 100m traveled, 15-min dive)
  • Depth accuracy: ±0.1m

Distance error grows with dive time and total travel due to IMU drift accumulation. Each surface re-acquisition of GPS resets accumulated error.

Note: navigation data is advisory only. Always defer to the dive site's safety procedures and your divemaster's instructions.

Q5How is this different from Garmin Descent or Shearwater?

The biggest difference: navigation is built-in by default.

  • Garmin Descent: $1,000+. Dive-computer-first; navigation is secondary
  • Shearwater Teric: $1,200+. Specialized for Tec / Rec dives, almost no navigation
  • Ocean MAP: $89.99 (planned). Installs on the Apple Watch Ultra you already own. Underwater navigation + digital map + supplemental safety info in one app

Dedicated dive computers still lead on raw sensor precision and ruggedness. Ocean MAP serves as their navigation supplement — specialized in position tracking and entry-point return.

Q6Do I need to bring my iPhone diving?

No — iPhone is not required during the dive. All core features (compass, map tracking, depth & safety info) run entirely on the Apple Watch Ultra.

iPhone comes into play after the dive: logbook, site map, statistics and notes. iCloud sync is automatic — leave your phone on the boat.

Q7Is there really no subscription? Will pricing change after launch?

Yes — one purchase, lifetime use. No monthly fee, no annual fee, no in-app purchases.

Pricing:

  • Planned price: $89.99 — one-time purchase, lifetime use
  • New dive sites and OS-version updates are free

Sync goes only through your own iCloud account. There is no server-side subscription model.

Q8When does it launch?

Ocean MAP is currently getting ready for its App Store launch. Launch dates and updates drop first on Instagram @oceanmap4.

Once it's out, you can install it straight onto the Apple Watch Ultra you already own.

Q9What languages does it support?

Ocean MAP supports 7 languages end-to-end: English · Korean · Japanese · Chinese (Simplified) · Spanish · German · French.

The app follows your Apple Watch / iPhone system language automatically, and you can switch in-app mid-dive.

Q10How is my personal information protected?

Ocean MAP has no account sign-up and no server account. Your personal data stays on your own devices.

  • Dive logs and GPS coordinates: stored only on your own iCloud — never uploaded to our servers
  • Anonymous usage stats can be turned off anytime in settings
  • When transit is needed, it's HTTPS (TLS 1.3) only

See the Privacy Policy for full details.

Didn't find your answer? Reach out at oceanmap44@gmail.com.