There isn’t a clear software solution in the answers, but there are workable tracking methods.

For portraits, use an ordering cue: have each swimmer write their name and details on a slip of paper as they arrive, then photograph in that same order. The paper slips give you the sequence so you can match names to image order later. A voice recorder can also work—say each swimmer’s name as they step in, then match the audio sequence to the photo sequence.

For swim meets, record race information and start time so you can match image timestamps to the correct race, heat, and lane. Identifying individual swimmers after that may still rely on lane assignment or visual clues such as team/club colors.

Another practical event workflow is to skip detailed identification during shooting: upload images after each race or game to a local server or viewing stations, and let buyers browse and note the filenames they want. That reduces the need to identify every athlete while you shoot, though it requires more hardware.