Ocelot - Preserved since 1992 at Chatham Historic Dockyard.
Otus - Preserved at Sassnitz, Germany.
Onslow - Preserved at the Australian National Maritime Museum.
Ovens - Preserved since 1998 at the Western Australian Maritime Museum.
Riachuelo - Preserved at the Navy Cultural Centre, Rio de Janeiro.
Ojibwa - Preserved since 2012 at the Elgin Military Museum.
Onondaga - Preserved since 2009 at the Site historique maritime de la Pointe-au-Père.
O'Brien - Preserved in Valdivia, Chile.
Orion - Fin preserved at Rockingham Naval Memorial Park.
Otway - Fin and upper casing preserved at Holbrook, New South Wales.
Oxley - Fin preserved at HMAS Stirling. Bow preserved at the Western Australian Maritime Museum.
Not sure you can count the last three as they aren't complete.
https://en.wikipedia.org/wiki/List_o...ass_submarines