Swamp based Modules

[Ogrork the Mighty]

The ruined city of Xak Tsaroth from the Dragonlance module, Dragons of Autumn (3.5) takes place in a swamp.

 

[dead]

Treasure of the Black Veils is a free WotC adventure set in swampy environs:

FREE Original Adventures: Treasure of the Black Veils by Skip and Penny Williams

 

[the Jester]

I'm amazed nobody has yet mentioned U1-2. The Saltmarsh modules were great.

The early parts of Return to the Tomb of Horrors take place in a swamp, and have some cool, evocative stuff going on (ghouls that lurk in the water under floating mats of peat, and burst up to try to drag the pcs down... good stuff!).

 

[Ogrork the Mighty]

I should also mention the Age of Worms Adventure Path module, Encounter at Blackwall Keep (Dungeon #126). There aren't any ruins but there are some decent rules for swamp travel and dangers.

 

[demonsquidgod]

Hmm, I had already hinted that there might be lizardmen dwelling in the swamp, can you tell me more about Tomb of the Lizard King?

 

[roguerouge]

1st edition module Ravager of Time has a swamp excursion... and the best temporary smack down of uppity high level characters I'd ever seen.