Explain these fine fellows' unmentionables to me?

This photo popped up in my facebook feed with the caption "male beauty contest, early 1900s". Which is hilarious, but I'm sure, nonsense. I feel fairly certain that Edwardian male beauty contests were Not A Thing. Leaving aside whether these chaps would get through the first round or not.

But what is going on here - are these swimming trunks? I thought they would have an upper body piece as well, if the early 1900s date is right. Or are they underpants? I can't quite believe this is what Edwardian gentlemen wore beneath their fine suits?

For your viewing, err, pleasure:

 

@Retro Ruth no idea but hilarious!

 

It's a particularly fine collection of 'taches.

 

Glad it's not just me!

 

20s or 30s would make more sense. Not sure about that very long waxed 'tache for then, though, unless as you say it was for a laugh.

 

I'm kind of getting this vibe—


Are you looking for a knitting pattern so you can make one of those pairs of pants yourself Ruth?

 

Of course, I want a matching his-and-hers set for me and my man.

 

I bet @Jonathan could tell a lot by evaluating their shoes. The pair the second fellow from the left is wearing looks potentially dating-helpful

 

I just found this at vintagedancer.com, dated 1924. But I think these are women's - not sure if men's bathing shoes were drastically different.

 

I thought taches were shorter by the 30s. Third from right seems more 1900s to me.

 

What is the Polar Bears swim club, Barbara?

 

I'm not Barbara, but I do know there is a tradition in many colder climes here in the US for brave (or foolish) swimmers to jump into the nearest body of water together on New Years day.

Edited to add: But if I was a Polar Bear Club member, I'd be trying to wear more bathing suit, not less!

 

Ah we have that tradition on New Year's Day too, and plenty of cold water for it, but not by that name. I don't think we have a name for it!

 

To be honest, if that's for swimming... some those trunks don't look like they'll slip off as soon as they get wet...

 

Good point!
You know, now that I look more closely at the "garments", I can see a drawstring at the waist of 5 out of the 6. The 6th man - middle left - looks like he rolled his one-piece suit down to keep up with the Joneses.