I'm headed to the Florida Keys in mid-May and will be staying in Marathon...I only have a half-day available one of the mornings to fish while I'm there, but would love to get on some Mahi. It'll be me and my wife fishing for sure, but another couple may join us. Does anyone have a charter recommendation for me in that area?

Let me just say this about Keys fishing , if a guide down there has openings within 60 days , there is something wrong.
You might get real lucky and find a good captain with a cancellation. I have booked 6 months to 18 months in advance to get the dates I wanted ( May is a good time ) My favorite Captain in Key West told me he was doing
90% repeat business , and most of his clients would book their next trip before they stepped off the boat.
One of the reasons I have not been back in the past couple of years , he quit guiding and moved to California.

Good luck
Mo