I paid attention last time we flew a charter to SJU for a connection. Memory tells me it was 25 min from when we landed to checking in at American. There is a lot of walking at SJU. The ag department baggage scan was quick, used the AA kiosks, but TSA was backed up down the terminal. We have PreCheck and we were in line for 25 min. This was a cruise ship turnover day so the airport was a zoo. On a weekend, I would allow at least two hours min.