Finland AIS Vessel Tracker

{{ selectedVessel ? (selectedVessel.name || 'Unnamed vessel') : 'AIS Snapshot' }}

{{ selectedVessel ? summaryLine : (loading ? 'Fetching AIS snapshot...' : 'Lookup Finnish AIS vessels by identifier, name, type, or radius.') }}

{{ vessels.length }} vessel{{ vessels.length === 1 ? '' : 's' }} Fintraffic snapshot {{ selectedVessel.shipTypeLabel }} {{ selectedVessel.speedLabel }} {{ selectedVessel.headingLabel }} {{ selectedVessel.navStatusLabel }}

Vessel lookup

Search term:

Use MMSI 230685000, IMO 9811000, a callsign, or a vessel name; blank shows a capped snapshot.

Match field:

Auto detects 9-digit MMSI and 7-digit IMO values; choose Callsign or Name for text searches.

No vessels found for the current filters. Try widening the type, removing radius limits, or searching by MMSI/IMO.

Vessel type:

Choose Cargo, Tanker, Passenger, or another AIS group; Any keeps all reported types.

Hide stationary vessels:

On focuses on moving traffic; Off keeps stopped, moored, and anchored reports.

Result cap:

Accepted range: 1-200 vessels; lower caps are easier to review and export.

results

Center point:

Enter decimal latitude and longitude, for example 60.1699 and 24.9384.

Radius:

Enter kilometers such as 25 or 50; leave blank to sort by distance without cutting rows.

#	Name	MMSI / IMO	Type	Speed / Heading	Destination
{{ row.rank }}	{{ row.name }}	{{ row.identity }}	{{ row.type }}	{{ row.speed }} {{ row.heading }}	{{ row.destination \|\| '-' }} {{ row.coord }}
No vessels match the current filters.
Loading latest positions...

Check	Status	Evidence	Next action	Copy
{{ row.check }}	{{ row.status }}	{{ row.evidence }}	{{ row.action }}

No speed profile rows available

This AIS snapshot has no numeric speed values to render in the chart.

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Automatic Identification System, or AIS, is a maritime radio reporting system that lets vessels and shore services see nearby traffic with identity and movement data attached. A typical AIS picture answers practical questions about who is nearby, where the report placed the vessel, how fast it was moving, and which direction it was making good over the water.

In Finnish waters, a recent AIS snapshot can support harbor checks, dispatch notes, pilotage awareness, and routine vessel identification. A ship name alone is often weak evidence because names can be reused, shortened, misspelled, or shown with old variants. Identifiers such as MMSI, IMO number, and callsign reduce that ambiguity when they are present and current.

AIS snapshot flow from vessel report to source snapshot and reader checks for identity, movement, radius, and map position.

AIS rows are most useful when identity, position, movement, and source freshness agree. A vessel with the expected IMO number, plausible coordinates, and a sensible speed is stronger evidence than a name-only match. A vessel with stale destination text or missing coordinates may still be real, but the row needs a slower read before it is copied into a dispatch note or operational log.

The main limit is time. AIS can update quickly at sea, but any search view is still a published snapshot of reports that have already happened. It can show where a vessel was last reported and what the transmitted fields said, but it cannot prove where the vessel is now, forecast a route, or explain why a report is missing.

Use AIS snapshots for awareness, planning, and record checks. Do not use them as the only basis for collision avoidance, emergency response, or bridge navigation decisions.

Technical Details:

AIS combines static identity fields with changing voyage and movement fields. MMSI identifies a maritime radio station, the IMO number identifies many commercial ships across name or flag changes, and the callsign helps with radio contact. Dynamic fields such as latitude, longitude, speed over ground, course over ground, heading, navigation status, and destination describe the reported state at the time the source accepted the message.

The Finnish source used here is presented in the interface as Fintraffic Digitraffic AIS 15 min snapshots and is queried through a public feature service. Fintraffic's own marine documentation describes vessel locations and metadata as AIS messages broadcast by vessels, and its AIS notes explain that class A position and metadata messages are provided with some filtering or modification. That matters because a missing class, an empty destination, or a surprisingly quiet vessel-type group may reflect source publication rules rather than empty water.

Search behavior follows deterministic matching rules before any table, map, or JSON view is built. Numeric identifiers are treated differently from names, type filters use AIS ship-type codes, and distance filters are calculated after returned rows have been decorated with coordinates.

Lookup and filter rules

Lookup and filter rules used by the Finland AIS vessel tracker
Input or setting	Rule used	Result effect
Auto detect with 9 digits	Matches the MMSI field exactly	Best for a known radio identity
Auto detect with 7 digits	Matches the IMO field exactly	Best for a ship identity that should outlast a name change
Callsign mode	Uppercase contains search against callsign	Useful when the radio callsign is known but formatting may vary
Name mode or text in auto mode	Uppercase contains search against vessel name	Broad discovery path that can return lookalikes
Blank search term	Queries the snapshot with current filters only	Returns a capped sample rather than an identity-specific result
Hide stationary vessels	Requires speed over ground greater than 0 kn	Removes zero-speed rows, including vessels that may be anchored or moored
Result cap	Clamped to 1 to 200 rows	Keeps review and export size manageable

When a center latitude and longitude are present, proximity is computed with the haversine distance on an Earth radius of 6,371 km. That is appropriate for a quick geofence-style planning radius, but it is not a charted route length and it does not account for waterways, traffic separation schemes, or restricted areas.

d = 2 R arctan2 (\sqrt{a}, \sqrt{1 - a})

a = {sin (\frac{Δ φ}{2})}^{2} + cos (φ_{1}) cos (φ_{2}) {sin (\frac{Δ λ}{2})}^{2}

Variables used in the AIS radius distance formula
Symbol	Meaning	Unit
`d`	Great-circle distance from the entered center point to the reported vessel position	km
`R`	Earth radius constant used by the calculation	6,371 km
`phi`	Latitude converted from degrees to radians	radians
`lambda`	Longitude converted from degrees to radians	radians

AIS fields surfaced in results

AIS identity, movement, and quality fields shown by the tool
Field family	Examples shown	How to read it
Identity	MMSI, IMO, callsign, name	Use the strongest identifier available before trusting a name match
Movement	Speed over ground, heading, course over ground, navigation status	Compare speed, direction, and status before deciding whether traffic is moving, waiting, or unclear
Voyage text	Destination and ETA when provided	Treat as vessel-entered information that can lag the actual plan
Position	Latitude, longitude, coordinate string, map marker, distance from center	Good for rough awareness and radius filtering, not for precise navigation
Position quality	Position source, position accuracy, RAIM flag	Available in the decorated JSON when the source publishes those values
Vessel characteristics	Ship-type label and draught when available	Helpful context for traffic class, but not a substitute for official vessel particulars

Ship-type groups

Ship-type code groups used by the vessel-type filter
Filter label	Included AIS ship-type codes	Boundary note
Cargo	70 to 79	Includes values greater than or equal to 70 and less than 80
Tanker	80 to 89	Includes values greater than or equal to 80 and less than 90
Passenger	60 to 69	Includes values greater than or equal to 60 and less than 70
High speed craft	40 to 49	Includes values greater than or equal to 40 and less than 50
Service / SAR	50 to 59 and 30 to 39	Broader than the visible 50x hint because workboat-style 30x values are included too
Fishing	30 only	Can be sparse if the upstream source filters fishing-vessel messages
Sailing / pleasure	36 or 37	A narrow recreational subset inside the wider 30x range
Other / undefined	0 or 90 and above	Catches undefined and out-of-group values

Everyday Use & Decision Guide:

Start with the identifier that leaves the least room for confusion. A 9-digit MMSI or 7-digit IMO number is better than a vessel name, and a callsign is often better than a partial name when radio identity matters. Leave Match field on Auto detect when you have a clean numeric identifier; choose Callsign or Name contains when the text itself is the evidence you have.

The page loads a default capped snapshot, so a blank Search term can still be useful for a quick scan. Treat that view as a sample shaped by Result cap, Vessel type, and any advanced filters. It should not be read as every vessel in Finland or every vessel near a port.

Use the advanced controls when the question is about a place rather than one ship. Enter separate decimal values in Center point, then add Radius in kilometers if you want a hard cut-off. With a center point but no radius, the list is sorted by distance. With both, rows beyond the radius are removed.

Hide stationary vessels is helpful for approach traffic because it removes zero-speed rows. It can also hide the exact vessels you need for anchorage, berth, lay-by, or waiting-area checks. Leave it off when stopped traffic is part of the question.

Before copying or exporting a result, compare three things: the MMSI / IMO cell, the Speed / Heading cell, and the coordinate text under Destination. If those do not tell a consistent story, widen the search or switch to a stronger identifier before using the row in a report.

Step-by-Step Guide:

Check the initial Showing ... vessels line if you want a broad snapshot, or enter a Search term when you already know a vessel name, MMSI, IMO number, or callsign.
Set Match field. Use Auto detect for clean 9-digit MMSI and 7-digit IMO values; switch manually if a text query should search Callsign or Name contains.
Open Advanced when you need Vessel type, Hide stationary vessels, a smaller or larger Result cap, or a location-based radius.
For a harbor or pilot-station check, enter Center point latitude and longitude as two decimal numbers, then enter Radius in kilometers if the list should exclude farther traffic.
Press Lookup vessel and wait for either the source line, a No vessels found notice, or an error. If MMSI mode rejects a text name, change the match field instead of retyping the same value.
Review the Vessels table first. Use the focus icon on the intended row so the summary badges, AIS Vessel Map, and coordinate copy action all refer to the same vessel.
Open AIS Vessel Map only after the selected vessel has coordinates. Use Copy coords for a quick position note, or open a map handoff when you need visual context outside the table.
Use JSON, Copy CSV, Download CSV, or Export DOCX after you have checked identity and movement. The export is a record of the current view, not a historical track.

Interpreting Results:

The strongest row is one where the identifier, name, type, speed, heading, and coordinates all make sense together. If the name matches but the MMSI or IMO number does not, treat the row as a possible lookalike. If the identity is exact but the movement fields look stale, keep the row as a presence clue rather than a current-motion claim.

Zero speed means the reported speed over ground is 0 kn. It does not prove that the vessel is irrelevant, unoccupied, or permanently stopped. It may be moored, anchored, waiting, or reporting a stale value. A nonzero speed is also not enough by itself; compare it with heading, course, destination, and the map position before calling it an arrival or departure.

Distance from center is a quick inclusion test. A row inside a 25 km radius belongs in a planning scan around that point, but the calculated distance is not a berth distance, sailing distance, or safe-passage distance. Use it to decide what to inspect next, then verify high-stakes movement elsewhere.

An empty result usually means the filters are too narrow, the source did not publish a matching row in the current snapshot, or the result cap and sort order hid what you expected. Remove the radius, turn off Hide stationary vessels, set Vessel type back to Any, and try a stronger identifier before concluding that the vessel is absent.

Worked Examples:

Commercial vessel identity check

Enter 9811000 as the Search term and leave Match field on Auto detect. The lookup treats the 7-digit value as an IMO number, so the MMSI / IMO cell should show the same IMO if the current snapshot contains the vessel. If the table shows a familiar name but the IMO is missing or different, do not treat the match as settled.

Helsinki-area moving traffic scan

Leave Search term blank, set Center point to 60.1699 and 24.9384, enter 25 in Radius, and turn on Hide stationary vessels. The result line should read as a vessel count within 25 km of that center. Rows with zero reported speed are removed, so this setup is useful for moving traffic but poor for berth occupancy.

Too many name matches

A search for a short name fragment can fill the table with similar vessel names. Use the MMSI / IMO cell to identify the intended row, then rerun the lookup with that MMSI or IMO number. If the target disappears after you add Vessel type or Radius, remove those filters first; the broad name search may have been correct while the secondary filters were not.

FAQ:

Does the result show a continuous route?

No. It shows rows from the queried AIS snapshot and places the selected vessel on the map when coordinates are available.

Why does a blank search return vessels?

A blank search uses the current filters with a general snapshot query. The default cap is 50 rows, and the cap can be changed from 1 to 200.

Why might the Fishing filter return no useful rows?

The visible filter looks for ship type 30, but Fintraffic's AIS notes say fishing-vessel messages are filtered from the AIS messages it provides, so that group can be sparse or empty.

Are search values kept only in the browser?

No. A lookup sends the search and filter query to the public vessel-data endpoint, and the map loads external map tiles when opened. Copy and download actions happen from the current browser view.

Why can destination or ETA look wrong?

Destination and ETA are AIS voyage fields that can be old, blank, or entered differently from the current plan. Use them as context, then verify against identity, speed, heading, and position.

Can this be used for navigation safety?

No. It is a search and review view for AIS snapshots. Use certified navigation systems, official charts, bridge procedures, and current traffic services for safety-critical decisions.

Glossary:

AIS: Automatic Identification System, a maritime radio reporting system for vessel identity, position, movement, and related safety data.
MMSI: Maritime Mobile Service Identity, a 9-digit radio identity used in AIS and other maritime communication systems.
IMO number: A 7-digit ship identification number that normally stays with a qualifying vessel through name, ownership, or flag changes.
Speed over ground: Reported movement speed across the Earth's surface, shown here in knots with a kilometers-per-hour conversion.
Course over ground: The reported direction of movement across the ground, which can differ from the vessel's heading.
Navigation status: An AIS status code such as under way, at anchor, moored, restricted manoeuvrability, fishing, or unknown.
RAIM: Receiver Autonomous Integrity Monitoring, a position-integrity flag that may appear in the decorated JSON when the source publishes it.
Great-circle distance: The shortest distance over the Earth's surface between two latitude and longitude points, used for radius checks.

References:

Marine traffic, Digitraffic - Fintraffic.
AIS messages, Digitraffic - Fintraffic.
AIS feature service, ArcGIS REST Services.
Automatic Identification System overview, U.S. Coast Guard Navigation Center.
IMO identification number schemes, International Maritime Organization.

Finland AIS Vessel Tracker

Introduction:

Technical Details:

Lookup and filter rules

AIS fields surfaced in results

Ship-type groups

Everyday Use & Decision Guide:

Step-by-Step Guide:

Interpreting Results:

Worked Examples:

Commercial vessel identity check

Helsinki-area moving traffic scan

Too many name matches

FAQ:

Glossary:

References: