Will I miss my transfer or onward flight in Phu Quoc if immigration and customs take longer after an international arrival?

Even when the whole itinerary is booked as a single reservation (including connections between different airlines in the same alliance, e.g. Vietnam Airlines and China Eastern), check-in staff can usually see all onward flights and typically check baggage through to the final destination. However, this isn't guaranteed for every routing — a single booking can cover as many as 15 flights, and that doesn't necessarily mean baggage will fly through without being collected at some connection. Travelers recommend confirming directly with staff at the first check-in counter how baggage is being handled for the full route.

If your itinerary is a self-transfer that requires collecting and rechecking baggage at the connection, the risk of missing the next flight is higher because you must repeat the airport formalities after arrival. For inexperienced travelers, a single booking with bags checked through to the final destination is considered safer.

After an international arrival, immigration and customs can take extra time, and that is considered normal. In practice, an organized transfer bus usually does not leave until passengers complete the required formalities, but it is still wise to inform the guide or driver if you are running late.

Some travelers report that there can be a separate check-in line when flights are handled through guides or tour representatives. It may speed things up, but these services are usually priced higher than checking in on your own.

If both flights are issued under one booking with the same airline, it is treated as a through-ticket. In that case, if the first segment is delayed or canceled, the airline is responsible for moving you to another flight rather than leaving you to solve it yourself.