No.7 (第七号掃海艇, Dai Nana Gō Sōkaitei), also sometimes called W-7 was a No.7-class minesweeper for the Imperial Japanese Navy.

The convoy arrived at Lamon Bay late at night, and conducted mine-sweeping operations.

On 7 January, W-7 and MineSweepDiv 21's remaining ships, W-8, W-9, W-11 and W-12 (W-10 having been sunk On 17 December, W-7, along with support from W-8, provided cover for the cruisers Kumano and Suzuya, light cruisers Yura and Kinu, seaplane tender Kamikawa Maru, destroyers Fubuki, Shirakumo, Murakumo, Shinonome, and Sagiri, the troop transport Hiyoshi Maru and a few subchasers during the invasion of Miri.

On 9 January 1942, MineSweepDiv 21's remaining ships left Magunaga Bay, with the light cruiser Nagara, the submarine chasers CH-1, CH-2, and CH-3, and patrol boats P-1, P-2, and P-34.

After its operations in the Dutch East Indies, W-7 was assigned a series of escort and minesweeping jobs.

Almost an hour after being hit, W-7 "emitted a huge sheet of flames and slowly sank", according to HMS Storm's log.