South Penghu Marine National Park consists of Dongyuping Island, Siyuping Island, Dongjiyu, Xijiyu, and surrounding reefs. It is a major ecological tourism destination, with a secret lavender forest underwater. The underwater coral reefs are covered in purple hues, visible from the shore, creating a magical scene. 
  
Dongyuping Island 
Dongyuping Island is the last volcanic lava island formed in Penghu. The surrounding waters have an exceptionally high coverage of coral reefs and rich underwater ecology. The land, which remains underdeveloped, still retains the traditional Penghu houses made of basalt and coral reef rocks, as well as the stone wall garden farmhouses. The island settlements are mainly located in the lowlands on the western and southwestern sides. The buildings are mostly traditional Minnan-style architecture, arranged along the hillsides, facing away from the wind. On the slopes along the north-south roads, you can find expansive stone wall gardens and terraced fields, evoking the agricultural life of the past. In addition, on the rear mountains of Dongyuping Island, there are many basalt joint formations, including ocean-erosion ditches, sea pillars, sea caves, as well as geological features formed by the cooling of lava at different rates, resulting in both columnar and plate-like joint patterns. 
  
Siyuping Island 
Located to the northwest of Dongyuping Island, Siyuping Island is a quadrilateral mountain terrain. Due to its geography, villages could not cluster around the port and instead settled on flat areas at the hilltops. Since there are no wind-sheltered valleys on the island, most settlements are concentrated in low-lying plateau areas. The road from the dock to the inland village is about 50 meters long, known as the "Hero Slope(好漢坡)." As you pass the slope, you can see traditional Penghu houses made of stone and basalt.Since most of the villages are located in the southern end, the northern end has fewer structures. Therefore, the geological landscapes in the northern area are more diverse, including a coast made up of large gravel and a small island called Xiaotiejhanyu (Small Tiejhanyu) visible to the left of the gravel shore. From a distance, you can also see Toujinyu (or Toujinyu Island.) Most of the local residents have moved away and many houses have been damaged over time. Currently, the most well-preserved structure is the Huaniang Temple, where you can trace the island's past glory through its golden furnace and temple architecture. 
  
Dongjiyu 
Also known as Dongji Island, Dongjiyu is a key point on the Taiwan-Penghu shipping route and has historically been an important transshipment station for maritime trade between Taiwan and Penghu. During the Japanese occupation, in order to secure Taiwan-Penghu control, military camps and lighthouses were built at both the northern and southern ends of the island, with troops stationed to guard the surrounding sea areas. The Dongji Lighthouse, built in the north, was the highest point on the island and served as the first sea barrier between Taiwan and Penghu. Local residents graze sheep on the island, and if you climb the hills, you can see many black-and-white sheep grazing and resting, creating a peaceful scene. 
  
Xijiyu 
Also known as Xiji Island, Xijiyu is an important point on the Taiwan-Penghu shipping route. Due to its remote location and inconvenient transportation, the island's residents struggled to make a living, leading to a sharp population decline. On July 1, 1979, the entire population of Xiji Village was relocated with the help of the county government and the administrative region of Xiji Village officially became part of history. A famous attraction is the Xiji Blue Cave, a unique sea cave in Penghu, which has remained intact due to the lack of human disturbance, preserving its natural beauty.

Source: Penghu Travel