Sinister Secrets of Salt Marsh?

[Voadam]

Was Sinister Secret of Salt Marsh the 1e module where the adventure goes underwater?

 

[wizofice]

(D2) Shrine of the Kuo-Toa did. Don't think we ever played Saltmarsh.

 

[WmRAllen67]

U1: Sinister Secret of Saltmarsh didn't, but U3: The Final Enemy did...

Check this thread for more info:

http://www.enworld.org/forums/showthread.php?t=89262

 

[diaglo]

there is also an encounter in S2 White Plume Mountain that uses underwater travel.

but like WmRAllen67 i think you are looking for U3 The Final Enemy... the final module in the Saltmarsh series