Hi, I am considering a route which involves flying SQ to Istanbul, then taking a flight on Turkish Airlines made on a separate booking. (it cannot be combined into a single booking, unless anyone has a suggestion on how to do that).

Has anyone flown through Istanbul with SQ, then connecting to Turkish Airlines?

1. If I don't check in luggage and just bring a cabin bag on board, would I need to go out and go through immigration and security again? Or can I just move from one terminal to another? What is the airport like at Istanbul? The connecting time is about 2-3 hours.

2. If I do check in luggage (one piece), what are the chances of asking them to do an interline transfer so I don't need to collect the luggage and check in again?

Thanks for your advice.