What kind of ship is YOKOSUKA?

YOKOSUKA is a research vessel sailing under the flag of Japan, built in 1990 by Kawasaki Heavy Industries. The vessel is 105 m long with a beam of 16 m and has a gross tonnage of 4,439.

Who is recorded as the owner or manager of YOKOSUKA?

Japan Agency for Marine-Earth Science and Technology is recorded as Registered owner for YOKOSUKA (source: Wikidata). This source record does not independently confirm today’s ownership or management.

What sanctions and inspection records does Seadar hold for YOKOSUKA?

Seadar has no matched sanctions record displayed for YOKOSUKA from the OFAC SDN list, the UK Sanctions List, the Canadian autonomous sanctions list, the EU list of designated vessels and the New Zealand Russia Sanctions Register. Coverage may be incomplete; this is not sanctions clearance. No matched inspection records are displayed for YOKOSUKA. Missing records do not establish whether the ship has been detained.

YOKOSUKA

Research vessel · Japan · built 1990 · AIS Class A

IMO8711019MMSI431460000Call signJCOYLast AIS position Oct 1, 2026, 00:27 UTC

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In short

YOKOSUKA (Research vessel, Japan flag) was last seen on AIS on Oct 1, 2026, 00:27 UTC, under way at 7.4 kn, near Yokosuka (North Pacific Ocean). Seadar has no more recent AIS position for this ship. Its current location cannot be established from this report. Registered owner: Japan Agency for Marine-Earth Science and Technology (source: Wikidata).

Vessel type: Research vessel
Flag: Japan
Year built: 1990
Gross tonnage: 4,439
Size (length × beam): 105 m × 16 m
Registered owner: Japan Agency for Marine-Earth Science and Technology

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Photo of RV Yokosuka — Photo: 井上知樹 · Licence: Public domain · via Wikimedia Commons

Last reported position

received Oct 1, 2026, 00:27 UTC

Position: 35.2905° N, 139.6909° E
Area: North Pacific Ocean
StatusWhat do AIS statuses mean?: Under way using engine
Speed: 7.4 kn
Course: 220°
Heading: 225°

35.2905° N, 139.6909° E

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Seadar detected no port call in the last 30 days.

Port calls are detected by Seadar from AIS (at least 30 minutes slow inside a harbour area); see Port calls below.

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Identity & particulars

Name: YOKOSUKA
IMO numberWhat is an IMO number?: 8711019
MMSIWhat is an MMSI?: 431460000
Call signWhat is a call sign?: JCOY
Flag: Japan
Vessel type: Research vessel
AIS ship type: Other
Gross tonnageGross tonnage vs deadweight: 4,439
Length overall: 105 m
Beam: 16 m
Year built: 1990

A tag next to a value names the register that supplied it (hover or tap it for the record and date). Values without a tag come from the ship's own AIS broadcasts or from Wikidata. Position and identity are derived live from AIS.

Ownership & management

Each line shows where the fact comes from. Links backed by an identifier point to the company page.

Registered owner: Japan Agency for Marine-Earth Science and Technology
Source: Wikidata · reported · confidence 0.8 · retrieved Sep 22, 2026
Builder: Kawasaki Heavy Industries
Source: Wikidata · reported · confidence 0.8 · retrieved Sep 22, 2026

Timeline

Dated events for this ship from every source Seadar holds, newest first. Each line names its source; derived items say how they were derived.

Date	Event	Source
Jun 11, 2013	Reported arrival at San JuanAuthority-reported	USACE foreign traffic vessel entrances & clearances
Jun 11, 2013	Reported departure from San JuanAuthority-reported	USACE foreign traffic vessel entrances & clearances

Owner, operator and manager changes found by comparing yearly EU MRV reports are dated to the reporting year ("during 2025"), not to a day. Port calls here are the most recent only; the full lists are further down.

Port calls

Two kinds of evidence, kept apart: calls Seadar detected from the ship's AIS positions, and arrivals and departures published by port authorities and customs records.

Reported by authorities Authority-reported

Port	Record	Date (UTC)	Berth	Source
San Juan PRSJU	Arrival	Jun 11, 2013(date only)	—	USACE foreign traffic vessel entrances & clearances
San Juan PRSJU	Departure	Jun 11, 2013(date only)	—	USACE foreign traffic vessel entrances & clearances

Records published by the authority named on each row. Earliest record for this ship: June 11, 2013.

Source: US Army Corps of Engineers, Waterborne Commerce Statistics Center (US CBP entrance/clearance records). Licence: US Government work — public domain.

Frequently asked questions

Where is YOKOSUKA now?: YOKOSUKA (Research vessel, Japan flag) was last seen on AIS on Oct 1, 2026, 00:27 UTC, under way at 7.4 kn, near Yokosuka (North Pacific Ocean). Seadar has no more recent AIS position for this ship. Its current location cannot be established from this report.
What kind of ship is YOKOSUKA?: YOKOSUKA is a research vessel sailing under the flag of Japan, built in 1990 by Kawasaki Heavy Industries. The vessel is 105 m long with a beam of 16 m and has a gross tonnage of 4,439.
Who is recorded as the owner or manager of YOKOSUKA?: Japan Agency for Marine-Earth Science and Technology is recorded as Registered owner for YOKOSUKA (source: Wikidata). This source record does not independently confirm today’s ownership or management.
What sanctions and inspection records does Seadar hold for YOKOSUKA?: Seadar has no matched sanctions record displayed for YOKOSUKA from the OFAC SDN list, the UK Sanctions List, the Canadian autonomous sanctions list, the EU list of designated vessels and the New Zealand Russia Sanctions Register. Coverage may be incomplete; this is not sanctions clearance. No matched inspection records are displayed for YOKOSUKA. Missing records do not establish whether the ship has been detained.

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