You'll have to somehow get the germans to invade poland and start a war that turns all of europe into a trench-filled battlefield, and then go find yourself a nice trench
A one week patrol in combat boots through rice patties will do the trick .
Glastonbury in a very wet year.
My mate got it and had to have his leg amputated.
go through a ballpit in chuck E cheese's barefoot.
Nice, though I think the retro McDonald's ballpits that still exist around me would work better tbh, I don't think that those balls or the pit have ever been sterilized in their entire history, and I remember playing in them as a young kid...
I love how everyone seems to be answering this. But I want to know why you want trench foot! xD
Go climb mountain in a very cold rain, get stuck up there for about 5 days or more and you will get trench foot.