Originally Posted by
darthbimmer
The train seems like a decent alternative. I haven't used it yet since the train links were only completed recently. I've taken the bus many times.
The section from ICN-GMP has actually been running for a couple of years now, recently they just finished the rest of the line from GMP-Seoul Station
The train is about half the cost 3,300W (3$) to Gimpo Airport and takes 33 minutes, just make sure you don't get on an express train to Seoul Station.
The bus has a more comfortable seat, but I always take the train