All ships of the S-1 class:

Royal Navy (more on Royal Navy)

HMS P 553 (P 553) (ex. S-21)
HMS P 554 (P 554) (ex. S-22)
HMS P 552 (P 552) (ex. S-1)
HMS P 555 (P 555) (ex. S-24)
HMS P 556 (P 556) (ex. S-29)

Polish Navy (more on Polish Navy)

ORP Jastrzab (P 551) (lost 2 May 1942)

US Navy (more on US Navy)

S-1 (SS-105) (Loaned to the Royal Navy as P 552)
S-18 (SS-123)
S-20 (SS-125)
S-21 (SS-126) (Loaned to the Royal Navy as P 553)
S-22 (SS-127) (Loaned to the Royal Navy as P 554)
S-23 (SS-128)
S-24 (SS-129) (Loaned to the Royal Navy as P 555)
S-25 (SS-130) (Loaned to the Polish Navy as Jastrzab)
S-26 (SS-131) (lost 24 Jan 1942)
S-27 (SS-132) (lost 19 Jun 1942)
S-28 (SS-133) (lost 4 Jul 1944)
S-29 (SS-134) (Loaned to the Royal Navy as P 556)
S-30 (SS-135)
S-31 (SS-136)
S-32 (SS-137)
S-33 (SS-138)
S-34 (SS-139)
S-35 (SS-140)
S-37 (SS-142)
S-38 (SS-143)
S-40 (SS-145)
S-41 (SS-146)
S-36 (SS-141) (lost 20 Jan 1942)
S-39 (SS-144) (lost 16 Aug 1942)

6 submarines of the S-1 class lost.