Travel to Sokcho Beach.

If you're visiting South Korea and want to enjoy the beach without going all the way to Busan, I recommend heading to Sokcho. You can buy a ticket at the bus terminal for around 20,000 - 27,000 won, depending on the type of discount, and the journey takes just over 2 hours. It's a good idea to stay for two days and one night, or three days and two nights. Sokcho is close to Gangneung and Yangyang, so you can visit those two provinces as well. There are plenty of accommodations and hotels near the beach, so you can easily walk from your lodging to the sea. It's very convenient and the atmosphere is great.