On RCI B2B's your 2nd boarding card is normally delivered to your cabin on the last night of the first cruise. No you do not check in again, either stay on the ship or go ashore as you would at any other port of call. You tip at the end of each cruise as staff get moved around cruise by cruise....Wilba.
It was late when I wrote that last response. Forget the word 'Boarding Card'!!! It should read 'Seapass' card, so I'll Start again.........You will only receive a 'Second Seapass Card' if you are changing cabins. If you are in the same cabins you will receive a final statement after the first cruise & your account will start again using your original Seapass Card for the second cruise. They may request you to go to the Guest Relations Desk & get your card re swiped.
We are doing a B2B in the Caribbean and on returning to Fort Lauderdale we have to leave the ship and come back on again to satisfy the american immigration, unless I can find away around this.
If your b to b is in US you will have to go threw immigration. All b to b meet and are given new sail@sign cards. You might have to change dinning table. Tip one week at a time. If cruise in Med you dont have to go to immigration. Hope you have same cabin. enjoy your cruise.