For those using public transport, bus is the most convenient way to get to Donghae for most people. The bus terminal is a 20 minute walk north of the downtown area (5 minute cab ride.) There are frequent buses to the Express Bus Terminal in Seoul (takes a little over 3 hours), and less frequent buses to Dong Seoul (East Seoul.) There are also buses leaving every 10 minutes for Gangneung (35-40 minutes) as well as buses to most other cities in Gangwon Province. There are 3 overnight buses to Busan.
The Yeongdong line goes through Donghae, stopping at Donghae Station (south of downtown) and Mukho Station (north of downtown.) There aren't a lot of trains, however, and those there are don't go to too many places that are appealing to tourists, making the bus more convenient for most tourists.
Donghae serves as the main access point to Ulleungdo, (51,000 won each way) with regular ferry service throughout the year (usually once or twice a day in each direction, more frequent in the summer.) Donghae also serves as the Korean stop in ferry service between Vladivostok, Russia and Sakaiminato, Japan . Ferries leave from Mukho Port, a 5 minute drive north of downtown.
Highway 65 ends in Donghae and connects the city to Gangneung further north. From Seoul take highway 50 to Gangneung which then leads to the 65.
South Korea uses a toll system for their inter-provincial highways. Seoul to Donghae costs W11,400 one way in tolls. However if you are a group of people (at least 3) driving is a cheaper option than the bus. The trip from Seoul takes about 3 hours when there is no traffic.
Mountains / Nature
Mureung Valley (무릉계곡) This is a fantastic valley with several hikes of varying difficulties. You can hike to waterfalls, temples or up mountains. Mureung valley stretches to the base areas of Mt. Dutasan and Mt. Cheongoksan. Admission to the valley is 1,500 won for adults. The valley can be reached by taking any of the city buses numbered 12-something (e.g. 12-4.) The bus fare is 1,000 won.
Yongchu Waterfall, Mureung Valley
Samhwasa Temple 삼화사. The historic Samhwasa temple, located at the entrance to Mureungdowon. It was built by a Buddhist priest named Jajangyulsa, during the reign of queen Seondeok of Shilla Dynasty. It has an iron Buddha statue.
Haksodae cliff 학소대. There’s a nice stream flowing here. According to legend, shinseon (a local god) built a house for red-crowned cranes.
Dutasan mountain 두타산. It’s a mountain.
Cheongoksan mountain 청옥산. It’s a mountain.
Dutasanseong, mountain fortress두타산성. A fortress.
Mureung square, Silgaeul (small stream) 무릉광장실개울. A resting place after climbing the mountain.
Gukhaengsuryukdaeje 국행수륙대재. A festival held every October. A cultural event to pray for the peace of the nation and people.
Cheongok natural cave 천곡천연동굴. Located in the middle of the city. There’s also a Nature Museum in Cheongok cave.
Yongchu waterfall 용추폭포, 33 meters tall. The rocks in this waterfall are supposed to look like a dragon.
Mureung Banseok 무릉반석. At the mouth of Mureung valley there’s a flat white rock slab of 4500m2. A good place to rest before you start seriously climbing.
Candlestick rock 능파대 (촛대바위). This is the rock that is sung about in the beginning of the Korean national anthem. Try to see it at sunrise.
Supyeongseon Festival 수평선축제. Includes: national beach volleyball competition; ‘Neulpureun’ sea festival; B-boy Battle contest; traditional fishery fieldtrips; sending a “wishing-postcard” to the horizon. Held every August. Location: Mangsang swimming beach. 033-531-1020
Squid Festival 오징어축제. Enjoy the culture of fishing villages, as well as seafood. Held every September. Location: around Mukhohang harbor landfill. 033-531-1020
Donghae Mureung Festival 동해무릉제. Promotes Korean traditional culture. Held in the first week of October. Location: Donghae Sports complex. 033-531-1020
Jeongwol Daeboreum Dalmaji Event 정월대보름달맞이행사. Daeboreum is the day of the first full moon by the lunar calendar. This festival celebrates Korean folk games and viewing the moon. Time: January 15th of the lunar calendar, every year. Location: Jeoncheon riverside. 033-522-5885
E-MART is the only big chain retailer in town. They offer everything from food to clothes and electronics (think wal-mart). Apart form them, there are a number of shops in the downtown area offering your usual services. English will be limited however and bargaining is not too common in the retail stores.
Donghae has limited food options but "Soma" is quite good. there are actually 2 locations located about a block away. They offer Korean food with a slight western twist (like pizza ddockboki and pork cutlet with pepper sauce), worth a try.
The fast food options are limited to KFC, Dunkin Donuts and Lotteria (the Korean McDonalds).
They have good pizza at Buena Pizza (try the bacon cheeseburger).
Of course, there are the ubiquitous galbi and kimbab restaurants.
However, those hoping for authentic western food may be disappointed.
Pizza Hut. There is a Pizza Hut on the 2nd floor of a building in view of Lotteria and Dunkin Donuts
Most of the options here are Hof and Soju bars that are all pretty much the same - they offer beer by the truckload (w2500 for 500ml) and soju. Many of them will expect you to order food as well since this is Korean tradition. Just politely say "no thanks" and most will leave you with you beer. Those looking for cocktails have to go to a cocktail bar and these are priced very highly. Your best bet is to head to E-Mart and get a few bottles of cheap booze if you want liquor.
Love Motels. As with everywhere else in Korea, love motels abound and Donghae is no exception. Don't be fooled by the name however, some of them can be seedy, however some can be quite special with huge beds and themed kitsch. Try the hotel "very six". A room with a pool table can be had for 90,000 won. Most rooms go for 50,000 won a night (more on weekends).
Jjimjilbang(찜질방). Donghae has a few of these as well. You can sleep in them for W6,000 a night (give or take). However its a communal experience and those looking for privacy won't find it here. For those that are willing to try a more authentic Korean experience, they are clean, safe and really cheap. The one close to the very six hotel is the best in town (near E-MART)
Beach Camping. You can set up tents in the designated camping area at Mangsang Beach, which is 8km North of Donghae City. Camping is free.