A self-transfer is when you connect between two flights that are on separate tickets, often different airlines. Search sites build these "virtual interlining" itineraries because they can be much cheaper.
What's different from a normal connection
- If the first flight is late and you miss the second, the second airline owes you nothing. You may lose that ticket.
- You often have to collect your bag and check it in again.
- You may need to pass immigration in the connecting country, so you might need a visa or transit permit.
How to do it safely
- Leave a long buffer: at least 3 hours, more for international-to-international or when bags must be re-checked.
- Fly carry-on only if you can.
- Check visa rules for the connecting country.
- See whether the booking site offers a connection guarantee and read what it actually covers.
- Avoid the last flight of the day for the second leg.