Recently had a colposcopy and the doctor took a sample of cells. Was only told to avoid tampons and not to have intercourse for 4 weeks. Is it safe to swim?

Pool, ocean, lake?
I personally would wait, just because of bacteria that might be present in any body of water, bacteria that doesn't affect you under normal circumstances.

Given how much bacteria is in bath water, I wouldn't even do that and only have showers for a while.