The Nordic Marine Instruments Østersøen is a 40 mm automatic dive watch with a wave-pattern dial, a Miyota 90S5 movement and manufacturer-rated 200 m water resistance. Its Danish-inspired design comes in several named colorways, while its 48 mm lug-to-lug length and 11.9 mm thickness are useful fit figures to consider before buying.
What is the Østersøen?
Østersøen is Nordic Marine Instruments’ automatic dive-watch line, designed with inspiration from Denmark and the Nordic seas. Time+Tide’s 2023 launch coverage describes the project as the work of Mick Jørgensen and Travis Tan, with Christopher Waluga as creative director. The original dial colors were Himmelblå, Havblå, Havgrøn and Arctic Hvid (Time+Tide launch coverage).
The collection’s defining visual feature is a wave-pattern dial. Nordic Marine Instruments describes it as a tribute to the sea; that is the brand’s design framing rather than an independent assessment. The brand’s official pages also list names including Midnat, Mørk, Arctic Hvid and Aventurine, so the launch lineup and the current catalog should not be treated as identical.
Specifications and fit
| Specification | Manufacturer-stated detail |
|---|---|
| Case diameter | 40 mm |
| Thickness | 11.9 mm |
| Lug-to-lug | 48 mm |
| Lug width | 20 mm |
| Bracelet taper | 20 mm at the lugs to 16 mm at the clasp |
| Maximum wrist fit | Up to 8.5 inches on official pages that state this measurement |
| Movement | Miyota 90S5 automatic |
| Case and bracelet | 316L stainless steel |
| Crystal | Flat sapphire with inner anti-reflective coating |
| Water resistance | 200 m / 660 ft |
| Crown and bezel | Screw-down crown; 120-click unidirectional bezel |
These are specifications published by Nordic Marine Instruments for variants with the relevant details listed. The stated water resistance is a manufacturer rating, not evidence of an independent dive test. The 48 mm lug-to-lug measurement is especially relevant for fit: case diameter alone does not show how far the watch spans across the wrist.
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- COMPREHENSIVE DIVE TRACKING FUNCTIONS - Built-in depth gauge dive timer surface recovery tracking and temperature monitoring provide essential freediving metrics helping improve safety performance and consistency for both beginner and experienced divers
- MULTI FUNCTION DIVE WATCH DESIGN - Includes stopwatch countdown timer world time five programmable alarms and long-term calendar delivering versatile everyday use beyond diving making this wrist computer a reliable tool for travel training and outdoor activities
- DURABLE WATER RESISTANT CONSTRUCTION - Engineered for harsh underwater environments with 100 meter water resistance rugged housing and lightweight compact design ensuring long lasting reliability comfort and performance for freediving spearfishing and snorkeling
Dial variants and availability
The original collection used four Nordic-sea-inspired names: Himmelblå, Havblå, Havgrøn and Arctic Hvid, as reported by Time+Tide in 2023. Current official pages show additional named versions, including Midnat, Mørk and Aventurine. Colorway names and stock can change, so check the brand’s product pages for the version currently offered.
At the time reflected by the official product-page information, listed pricing was $699 USD, and some versions were marked sold out. Price and stock are snapshots, not guarantees of current availability. The published material does not establish shipping charges or tax treatment.
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- LIGHT-POWERED QUARTZ - Converts ordinary light into stored energy through an ML2016 rechargeable cell. A full charge keeps the watch running for up to 6 months in darkness, with no charging cable needed.
- 200M WATER RESISTANCE - Rated to 200 meters/660 feet for swimming, snorkeling and water sports. Always screw the crown fully closed before water exposure; never adjust it underwater. Not for showering, bathing or sauna use.
- SCREW-DOWN CROWN - The threaded crown and double-seal structure help support water resistance and prevent accidental time changes. Unscrew and pull to set the time, then press and turn clockwise until secure.
- BOLD, EASY-READ DIAL - Oversized hands, raised hour markers and strong contrast make the time easy to read at a glance. The textured grid dial and minute-marked bezel create a rugged, ocean-inspired look.
- ACTIVE-WEAR COMFORT - The flexible textured strap stays comfortable and secure through daily use and water activities. After saltwater exposure, rinse the watch with fresh water and dry it thoroughly.
Bracelet, sizing and strap changes
The bracelet’s stated 20-to-16 mm taper gives it a narrower profile at the clasp than at the case. For a different look or feel, the official specifications list 20 mm lugs and quick-release spring bars, which provide a route to changing straps. Customer reviews on the Havblå product page mention nylon and FKM rubber alternatives; those are reviewer reports, not tested recommendations or confirmation that every 20 mm strap will fit without issue.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What the published specifications do—and do not—establish
The available manufacturer details describe the watch’s construction and intended capability, but they do not establish measured accuracy, independent water-resistance performance, or comparative durability. No side-by-side test against another dive watch is established in the cited material. Treat the movement, water-resistance rating and construction as stated specifications rather than independently verified performance results.
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- 【Engineered for the Deep】This professional dive watch logs key data for up to 200 dives, tracking depth, duration, and water temperature. With a maximum depth rating of 50M (10ATM), it also provides essential vibration alerts for time limits and safety intervals.
- 【All-Terrain Partner】Equipped with an accurate altimeter, barometer, and digital compass, this watch measures altitude changes, monitors pressure trends, and provides directional guidance. This makes it perfect for hiking and marine exploration, and your ideal tool for adventure.
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- 【Rugged Design, Uncompromised Visibility】Take on the toughest environments with confidence. Its rugged build and 10ATM waterproof rating offer unwavering protection. Paired with a brilliant EL backlight, your vision stays sharp—from the ocean depths to twilight trails.
- 【Magnetic Charging & 30-Day Runtime】Features convenient magnetic charging and a long-life lithium battery that provides around 30 days of standby, so you can focus on your adventures.
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- BUILT FOR TOUGH, ACTIVE DAYS Handle outdoor routines and daily wear with confidence. 42mm 316L stainless steel case delivers strength and durability, making it a reliable rugged option for men who need performance in real-world conditions.
- RELIABLE TIME YOU CAN TRUST DAILY Stay on track from work to weekend activities. Swiss-made Ronda 515 quartz movement delivers accurate, consistent timekeeping you can depend on throughout your day.
- DESIGNED FOR WATER AND ACTIVE USE Move from daily wear to time in the water with ease. Unidirectional rotating bezel helps track time during swimming and outdoor activities, making it a practical dive watch for active lifestyles.
- READY FOR SWIMMING AND WATER EXPOSURE Built for everyday wear and ready for swimming or time in the water. Water resistance up to 100M (330FT) supports underwater use and active environments without added stress. The best gift for an active man anyday.
- PRACTICAL DESIGN FOR EVERYDAY CONVENIENCE Keep your day organized without distraction. Date display adds quick access to daily information while maintaining a clean, easy-to-read dial for regular use.
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- Solar powered quartz movement helps reduce frequent battery replacement.
- 300M water resistant design supports swimming, snorkeling, diving, and water sports.
- Luminous hands and markers improve readability in dark or low-light conditions.
- Durable case and mineral glass are built for outdoor and everyday wear.
- WATCH SIZE & WRIST FIT: Features a 45.8 mm (1.80 in) case diameter and a 51.4 mm (2.02 in) lug-to-lug length. The adjustable 24 mm silicone strap accommodates wrists up to 230 mm (9.1 in). Measure your wrist and check the case dimensions before ordering, especially if you have a smaller wrist.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
