A good way to get around and see the highlights of Seoul is by taking a hop on hop off tour bus. Starting at DDP (Dongdaemun Design Plaza) you can get tickets (a wrist band) to board and exit the buses throughout the day and try to fit in whatever it is you want to do.
Seoul Sightseeing Bus’s offer three routes or courses/lines. The blue line which offers the modern highlights, the red line which offers the traditional culture highlights, and the last one which offers beautiful night views. The red and purple line stay north of Han river and stop at traditional markets, museums, palaces, gates, and shrines. The blue line goes south-east and crosses the Han river visiting Seoul forest, Lotte world and tower, rose square museums and universities.
For an extra 5,000 won you can get a ticket that includes transfers between lines, but do this at DDP. The red line and blue line tours are 15,000 won each and the night bus tour with the purple line is 12,000 won.
The buses are double-decker buses which means you can sit upstairs in the elements or downstairs in comfortable seats. I sat upstairs to get pictures that weren’t blocked by the windows. However the trade-off was to sit in uncomfortably hot plastic seats, unable to hear the recorded voice of the tour, and getting buffered by wind that caused me to spend most of my time holding onto my hat and hoping I wasn’t going to get sunburnt.
The starting point for all three lines is at the DDP, Dongdaemun Design Plaza. Purchase/ pick up your tickets near the road at a booth outside of A3 Art Hall. This is where you’ll get the day’s schedule and itinerary so that you can catch the next bus and figure out where you want to get off. The buses come every forty minutes starting at 9:30am. Make sure you arrive ten minutes early. The last main ones finish around 5pm.
Edit June 2019: It looks like Sky has changed to Yellow Balloon City Bus. You can check out the routes and find more information on the buses here.