Originally Posted by
WilcoRoger
Very much doable. Come off the plane, follow the transit signs, go through transfer security (you'll be the only pax, probably) and up the stairs, back to the departure area. I did quite a few transfers at ICN, even though not same plane turnarounds, but to utilize the Chinese 72/144 hrs TWOV opportunities and/or save a bunch to JPN.
The trick to ICN airside turn arounds are
a) make sure you have onward boarding pass or other "proof" of travel, like printed e-ticket
b) be very location aware and do not transfer between concourse/main terminal
because: Transfer security demands proof of onward travel, but transfer desks are located after security! And leaving concourse means no airside way back.