For travelers planning a short trip to South Korea, a suggested five to six-day itinerary includes landing at Incheon International Airport and exploring key attractions in Seoul. This route is optimal for couples who wish to experience the vibrant culture and scenery of South Korea.

For a more extended visit, a two-week itinerary could include starting in Seoul for a few days, visiting the DMZ, then traveling to Seoraksan for hiking, followed by a trip to Busan and its environs, and finally flying to Jeju before returning to Seoul. This itinerary is suited for families or groups interested in a mix of historical and cultural sights and natural landscapes.

Some travelers have recommended adjusting the number of days in each location based on personal interests, such as extending stays in Seoul or Jeju for deeper exploration. Engaging local travel operators for transport and accommodation arrangements can enhance the trip, making it more enjoyable and efficient.

According to forum posts, many travelers recommend visiting historical sites like Gyeongbok Palace, which opens at 9 AM, and exploring cultural areas such as Insadong. These sites offer a rich glimpse into Korea's history and traditional culture.

Travelers have called out Seoul's vibrant outdoor scene, with options like hiking, which is considered a national pastime. Places like Namsan Park and various palaces offer beautiful landscapes and are accessible via Seoul's efficient metro system.

For those interested in shopping and experiencing local markets, posts suggest visiting areas like Myeongdong for shops and restaurants. Gwangjang Market is specifically recommended for those looking to dive into local food culture and street food.

Some users pointed out that Seoul has a good mix of modern attractions. Areas like Gangnam are noted for their shopping malls and contemporary vibe, providing a contrast to the historical aspects of the city.

According to forum posts, travelers can purchase KTX train tickets from Seoul to Busan directly at the station or book in advance via the official website, LetsKorail.com. Advance booking is recommended to ensure seat availability, especially during peak travel times or weekends.

Some travelers mentioned that the high-speed KTX train is the preferred mode of transportation between Seoul and Busan due to its speed and convenience. The journey typically takes around 2.5 hours, making it a quick and efficient option compared to other forms of travel like buses or cars.

According to forum posts, multiple ferry services operate between Busan, South Korea, and various destinations in Japan. Notable services include Camellia Lines, which runs between Busan and Hakata, and JR Kyushu Jet Ferry, operating the Queen Beetle jet foil from Busan to Fukuoka. Additionally, the Kobee ferry and PanStar provide services to Tsushima Island.

Some travelers mentioned that Camellia Lines ferries usually depart in the late evening from Busan and arrive the next morning in Hakata. Travelers can book tickets for these services online or via phone. For JR Kyushu Jet Ferry, reservations can be made online, and the service is expected to cater to tourists once Japan reopens for tourism. Kobee's website primarily operates in Korean, but bookings can potentially be made through email contact provided on their website.

Moreover, services like Kampu Ferry connect Busan to Shimonoseki, with online reservations available about three months in advance. Travelers have also noted that ferries operate based on seasonal schedules, and detailed fare information might vary by room class rather than season.

According to forum posts, a Filipina with UAE residency needs to apply for a tourist visa to enter South Korea. Required documents include a passport, a visa application form, passport-size photos, proof of the purpose of the visit, proof of financial capacity, a round-trip ticket, a hotel reservation, health insurance, and possibly a police clearance certificate or a certificate of employment, depending on the specific circumstances of the visit.

Some travelers mentioned that US citizens can enter South Korea without a visa for tourist or business visits of less than 90 days. This temporary exemption is detailed on the US State Department website.

For travelers transiting through mainland South Korea to reach Jeju Island, a visa is required since they need to go through immigration at airports such as Incheon or Busan. Direct flights to Jeju are an exception where mainland visa requirements do not apply.

Travelers have called out that a single-entry visa is sufficient for travel from Seoul to Jeju and back since it's considered a domestic trip. However, for trips involving multiple entries, like traveling from South Korea to another country and back, a multiple-entry visa may be necessary.

Some travelers suggested using day-use rooms at transit hotels like Gimpo Airport Transit Hotel for those with a long layover in Seoul. These rooms allow you to rest and refresh without the cost of a full overnight stay.

For sightseeing during a layover, travelers recommended visiting central Seoul, including attractions such as Gwangjang Market, Insa-dong, and popular districts like Hongdae and Yeonnam-dong. These areas offer a rich cultural experience and extensive dining options, suitable for food enthusiasts.

For those leaving the airport, it was mentioned that you can store your luggage at the airport or potentially at the transit hotel, facilitating easy exploration of the city without the burden of carrying bags.

Regarding entry requirements, some posts indicated the need for a K-ETA visa for certain nationalities and stressed checking specific health and entry regulations, such as COVID-19 procedures or medication restrictions, before planning your layover activities in Seoul.

According to forum posts, credit and debit cards are widely accepted in South Korea, including for small transactions in convenience stores, taxis, and museums. However, some traditional markets, street food stalls, and smaller restaurants may require cash.

Some travelers mentioned the use of mobile payment apps such as Apple Pay, which is accepted in major convenience stores like GS25, CU, 7-Eleven, Lotte Mart, and Homeplus. Additionally, the T-money card is popular for transportation and can also be used for purchases in convenience stores.

Despite the prevalence of card payments, carrying some cash is advisable as certain places still operate on a cash-only basis. Travelers have called out the necessity of cash for street food and some traditional establishments. Furthermore, cash is required for loading transportation cards like the T-money card.

Several car rental companies were mentioned by travelers in South Korea, including AJ Rental Car, Lotte Rental Car, SK Rental Car, and Jeju Rent-a-Car. These companies offer various services, and travelers did not note any significant differences in service quality among them. Jeju Rent-a-Car was specifically recommended for those visiting Jeju Island.

Travelers have shared mixed experiences regarding booking and payments. Some faced issues with online and app bookings, particularly with payment processes only available in Korean. It was suggested that, in some cases, it is possible to reserve a car with just a reservation number and make payments upon picking up the car at the rental counter.

For those planning to rent cars, especially during peak seasons like July or for popular destinations like Jeju Island, early booking is advised. Prices can significantly increase closer to the date, and availability may become scarce. Some travelers suggested booking as early as possible to secure preferred rates and vehicle choices.