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Dive planning for Mats Mats Quarry

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Mats Mats Quarry Dive Planning
By  With (Reviewed 01/11/26)

From Dave Bliss’s Northwest Boat Dives book:

Dive Type: Artificial reef boulders

Degree of Difficulty: All divers

Tricky Stuff: Depth, approach

Overview: This is a working rock quarry, with tugs bringing barges in for loading and unloading. Immense cone-shaped rock piles serve as the north and south boundaries of the loading area for the quarry, and both piles are good dive sites. Their size, like the size of an iceberg, can be deceiving, with only the smaller portion of them being visible from the surface. The rock piles slope down to about 90 fsw, spreading widely in all directions.

The Dive in Depth: All levels of divers will enjoy this dive. Because the rock piles drop off fast, anchor close to one of them and swim to shore to start your dive. Descend to your desired depth and then explore the reefs from there back to the surface. Leave someone on board to guard against the wind or current swinging the boat into the rocks.

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⚠️ Before diving at Mats Mats Quarry, always check the site-specific wind/wave forecast, tide/currents, and recent reports (latest: Nov 29, 2025) !

Nearby Stations

7/8/26
NOAA Current XTide Current NOAA TidesMats Mats Quarry



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