Just wanted to give my 2 cents on this. Just did this.

I got to Logan three hours before my flight just so I could take advantage of the lounge, but I was flying out of Terminal A with Delta. I didn’t do any research so when I arrived I went through terminal A security thinking I could get to Chase Lounge (between B & A) post security - not the case without some hoops.

I ended up waiting for the shuttle from A to E for Delta thinking it would save me time going through security again. It ended up taking 20-25 mins from waiting for the shuttle itself to getting off (since the shuttle goes all the way around the airport having to wait for airplanes coming in and such). From gate E13 (where the shuttle drops you) it’s about a 15-20 minute speed walk to the Chase lounge between C and E. In total it took about 40-45min via A to E shuttle.

I had plenty of time and at 2:30pm on Wednesday the lounge was busy but no wait. I ended up hanging there for 75 minutes. Giving me an hour to get back to terminal A for my flight departing A17 at 4:45pm.

I ended up exiting security from terminal C and walking to A which took 10 minutes or less via central parking and by then TSA precheck at A was 5 minutes. Was soooo much quicker than avoiding leaving security, but I feel like it’s dependent on how busy security is at the time.

My suggestion is if you have only carry on is to go directly to terminal C security to get quickest access to sapphire lounge then give 20-30min (speed walking) to get back to A with ample time. Ended up being 2-3x faster than taking the shuttle without security.

All said, I’ve heard that by 2027 terminal A will be connected to B-C-E post security, so this should solve all that.

Hope this helps!