KOUUNMARU — Pleasure Craft · MMSI 431017858

KOUUNMARU has not broadcast an AIS position for 6 days. The most recent broadcast placed it in the Sea of Japan, on 1 Nov 2026, 09:40 UTC. It was sailing from CHOSHI to CLASS B. Vessels stop appearing on terrestrial AIS when they move beyond receiver range, so a gap does not necessarily mean the vessel is inactive.

KOUUNMARU broadcasts MMSI 431017858. The MMSI is the radio identifier used by AIS; the IMO number stays with the ship for life and does not change with re-flagging or sale.

KOUUNMARU is classified as a pleasure craft vessel registered under the JP flag. The vessel-type classification is derived from the AIS Type field broadcast by the ship's transponder; full pleasure craft fleet at /vessel-type/yacht and full JP flag list at /flag/jp.

MarineRadar shows the latest AIS broadcast from KOUUNMARU above, with current position, course, speed, and navigation status. Tap "View on map" to centre the live tracker on the vessel and watch its movement update in real time. The same data is available offline-friendly in the iOS and Android apps.

AIS transponders broadcast position every 2 seconds when underway at high speed and up to every 3 minutes at anchor. The position you see refreshes whenever the ship is in range of a coastal AIS receiver or a satellite pass — typically seconds in coastal waters and minutes offshore.

As a pleasure craft, KOUUNMARU sits in the same design class as the other pleasure crafts listed in the Similar Vessels section of the vessel page, or in the full pleasure craft directory at /vessel-type/yacht.