Originally Posted by
RohanDXB
...it is advisable to have sufficient time to make your connection though Delta will put you on the next flight if you miss. I suggest checking the Department of Transport's website for average processing times for the time at which your flight arrives. In places like JFK, 120 minutes and above can easily be spent at immigration. Not too sure about ATL.
Why create additional anxiety for no good reason? OP ought to relax. The DL service LHR-ATL will arrive in the afternoon. The customs / immigration workload at ATL is nothing like JFK. The three-hour layover OP has in mind ought to be more than OK. If it isn't, for whatever reason (inbound delay, weather, etc.) there will be about four more flights to Sarasota before day is done, and OP will be automatically rolled over to the next available seat. Nothing to worry about really.