# Open Waters (openwaters.io)

Open-source marine tools that plot nautical charts, seafloor depth maps, tide predictions, live vessel traffic and sun/moon almanac data.

- Atlas card: https://inite.ai/en/atlas/openwaters.io
- Site: https://openwaters.io
- For: Mariners, developers and ocean enthusiasts working with open marine charts, tides and vessel traffic
- Categories: dev
- Use 0/100 · alive 100/100

## Used for

- look up tide predictions for stations worldwide
- view depth contours and seamarks on nautical charts
- track live vessel traffic within a chosen area

## Price

Not read yet.

## For developers

- OpenAPI: https://openwaters.io/openapi.json (19 paths)
- API docs: https://openwaters.io/api
- MCP server: io.openwaters/ais (namespace; open on 2026-10-20, 6 tools)
- Read 2026-10-20

## MCP server, measured daily

Server: https://ais.openwaters.io/mcp, checked every day since 2026-10-20 (2 checks).

- Answered: measuring, 2 daily checks so far
- Median first answer: 543 ms
- Sign-in: none
- Context its tool definitions take: about 2195 tokens (6 tools)
- Tool definitions: A, 97/100
- Failing "params_described": 1 of 6 tools
- Method: https://inite.ai/en/atlas/mcp/report

## Your data

- Certifications stated: none
- Read 2026-10-20

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Source: INITE Atlas, https://inite.ai/en/atlas/openwaters.io. JSON: https://inite.ai/api/atlas/openwaters.io. MCP: https://inite.ai/api/mcp (atlas_lookup).