R
- Ran (Denmark): 237-ton Ægir class submarine
- Rauma (Norway): 355-ton minesweeper
- Rautu (Finland): 165-ton minesweeper
- Reiher (Germany): 109-ton training vessel, ex-West Diep (Belgium), became Warendorp
- Riilahti (Finland): 310-ton minelayer and antisubmarine escort
- Rio Pardo (Brazil): 132-ton submarine chaser
- Ristna (Estonia): 500-ton sidewheeler minelayer
- Rota (Denmark): 369-ton C class submarine
- Rucamilla (Chile): 435-ton submarine
- Ruotsinsalmi (Finland): 310-ton minelayer and antisubmarine escort
- Rybitwa (Poland) 183-ton minesweeper
- Ryś (Poland) 980-ton submarine
Read more about this topic: List Of World War II Ships Of Less Than 1000 Tons