While living in Seoul, South Korea is an amazing experience with so many restaurants, coffee shops and shops to explore, it can be overwhelming. That becomes even more true when you need to entertain your parents/friends when they come to visit.
I complied my top day trips that can be easy accomplished in one day without needing to rent a car or doing anything too complicated.
1. Sujongsa Temple
The Sujongsa Temple is a fairly short train ride away from downtown and offers an unparalleled view. Its only a thirty minute walk from Ungilsan Station (운길간) off of the G-J Line, through a small farm town. While the food options are limited (nonexistent really), its convenient location makes getting a meal at a different stop on the same line a breeze. There is an option to experience a traditional tea tasting experience in the building located to the far right of the image above. There is a fee to participate, but its only between 5,000-10,000 won, additionally the instructions provided are only in korean, but the staff was friendly.
There is no admission fee to enter the temple. Cost: 2,500 won for train
** Additionally, a ten minute from the Paldang Station, one train stop before Ungilsan, is the trail head to Yeabongsan (예봉산). This mountain has a 2.3 kilometers trail to the summit, which offers travelers two views of Seoul and the Han River. The end of the trail is the Sujongsa Temple, so the temple and the hike can be combined if you are looking for an all day activity **
I would consider this trail medium-difficult, due to its fairly steep gradient with conditions ranging from varying sized protruding rocks to steep stairs. When I hiked it, it was fairly popular but only with korean hikers. It seems to not be well known among western tourists/expats.
2. Nami Island + Rail Car
Nami Island is a beautiful island located in the center of the northern Han River. This tourist attraction became famous from the kdrama Winter Sonata, with little signs throughout the island with pictures of the drama. Many people come to take pictures of the lanterns hanging from rows of trees, as its an excellent couple photos opportunity. There are places to rent a bikes ranging from electric to tandem.
Nami Island can be easily reached by public transportation. The Namisum Gapyeong Ferry Dock is a short 6 minute bus ride (or 35 minute walk) from Gapyeong Station located on the Gyeongchun Line. There are two ways to get to the island, either by ferry, arriving every 10 minutes, and for the more adventurous a zip line. The island is easy to navigate with a circular shape and English maps readily available upon purchase of a ferry ticket. There was numerous cafes and restaurants throughout the island, though slightly over prices (to be expected). In addition, there was many manmade beautiful gardens, full of wildlife… strangely enough this includes 5 ostriches.
**The Gangchon Rail Park is located right next to Gimyujeong Station, four train stops away from Gapyeong Station. You can choose either 2 or 4 person self-pedaling rail cars that depart every thirty minutes, with a track that lasts between 20-30 minutes depending on your pace. On the track, you go through 4 tunnels with various themes. You then arrive at a rest area and take a 10 minute train ride along the Han River until you reach your destination, conveniently located next to Gangchon Station. **
This region is famous for Dakgalbi (닭갈비), a korean chicken dish, so there are numerous speciality restaurant throughout this area. This dish can be readily found in Seoul, but its very common for people to eat it here while traveling.
Seoul is regularly foggy when view from mountains 
Lotte tower can be seen in the distance
Cost: Varies depending on method to Nami Island and type of rail car
3. Ansan Mountain
Ansan Mountain is conveniently located inside Seoul, but feels like you were able to escape. I added this option to the list for those days you want to to get away without traveling too far. This mountain is located behind Yonsei University campus. There is no main entrance, but by getting off at Sinchon Station exit 3 and walking through Yonsei Univerity there are many hiking trails you can join. Trails can be easily found by talking toward the mountain while walking through the university campus.
The hike is easy-medium difficulty but rather short, only about 40 minutes to the summit. The view from the top is stunning! There is a special look out structure that allows for unobstructed views of Seoul and the surrounding mountains.
Cost: 2,000 won (train transportation)
4. Dreamy Camera Cafe and Yongmun Mountain
The Dreamy Camera Cafe is everything I wanted in a Korean cafe. With a great story, above average coffee and the most unique and beautiful exterior, I fell in love. This cafe is located closest to the Yongmun Station, the second to last stop on the G-J line. It’s not super easy to get to, probably best to a take a taxi there (about 10,000 won). The husband/wife owners both speak excellent English, and they can can call you a taxi. Ask them about the local waterfall, only 10 minutes away for some summer fun.
If you want to go hiking, the Yongmunsan is very convenient to get to as well. This 4 hour hike has a bus that runs from right outside the Yongmun station to the base of the mountain. If you are unfamiliar with the G-J line, it is normally heavily populated by older Koreans with bright hiking outfits all leaving the city for hiking or biking adventures. If you are going on the weekend, its very easy to follow the flow of people to get to base of the mountain. The trail runs partially along a small river/stream that is very peaceful.
Cost: 30,000 won (transportation + coffee)
