Center console fishing boat with an outboard motor tied to a lantern-lit dock at dusk, a common AMSOIL marine oil application

AMSOIL Marine Oil

Synthetic marine engine oil and gear lube for outboards, sterndrives, inboards, and personal watercraft that live in wet, high-RPM, hard-running service.

AMSOIL marine oil

Buy AMSOIL marine oil for outboards, inboards, sterndrives, personal watercraft, and boat gearcases. HP Marine and 100:1 Pre-Mix cover TC-W3 two-stroke outboards, with Synthetic Marine Gear Lube for the lower unit.

Buy online, or save up to 25 percent on every order by joining the AMSOIL Preferred Customer program for $20 USD per year. For local pickup, the where to buy AMSOIL guide covers the AMSOIL Dealer locator and how to find AMSOIL near you.

Order AMSOIL Marine Oil Online

Add an AMSOIL Preferred Customer membership to the same cart to unlock up to 25% off qualifying products. Existing members can sign in, and qualifying orders currently over $100 can ship free.

Marine Oil Products

Compare the full lineup below, then use the AMSOIL online lookup guide to confirm the formula and viscosity that fits your application.

AMSOIL 25W-40 Synthetic-Blend Marine Engine Oil staged in a marine and boat service setting

AMSOIL 25W-40 Synthetic-Blend Marine Engine Oil

AMSOIL Marine Oil

Four-stroke marine grade formulated for gasoline-fueled inboards, sterndrives, inboard/outboards, and personal watercraft.

AMSOIL 15W-40 Heavy-Duty Diesel and Marine Oil staged in a marine and boat service setting

AMSOIL 15W-40 Heavy-Duty Diesel and Marine Oil

AMSOIL Marine Oil

100% synthetic dual-purpose SAE 15W-40 lubricant for pre-emissions on-road and off-road diesels, marine diesel inboards.

AMSOIL 10W-30 100% Synthetic Marine Engine Oil staged in a marine and boat service setting

AMSOIL 10W-30 100% Synthetic Marine Engine Oil

AMSOIL Marine Oil

Premium synthetic 4-stroke formulation built for gasoline-fueled inboards, outboards, sterndrives, supercharged watercraft.

AMSOIL 10W-40 100% Synthetic Marine Engine Oil staged in a marine and boat service setting

AMSOIL 10W-40 100% Synthetic Marine Engine Oil

AMSOIL Marine Oil

Premium synthetic four-stroke marine formulation built for gasoline-fueled inboards, outboards, sterndrives, supercharged watercraft engines.