Grammar's fine, but it sounds a bit weird to me. I would rather say "... und treffen dabei viele Leute". That would say "we meet many people while we are swimming"

You could say "wir gehen schwimmen und treffen dort (e.g. at the pool/lake/seafront) viele Leute" as well.

Well you just put "We swim and meet people there." You should probably change that to "Wir gingen zum pool und trafen dort leute." We went to the pool and met people there.

Looks pretty much okay to me, I'm not fluent in German but the grammar looks correct.

Yes, this sentence is right LG Telpi

"Wir gehen schwimmen und treffen dort viele Leute."