4 Trails Ultra Loop, aka 4TUL, was created by Kenneth (PhotoGuava) . The loop starts and ends at Tai Mo Shan Lin Jie's kiosk. The loop is about 189km (Route189) in total with cumulative elevation gain of 5,200m. 95% of the 4TUL route falls within Hong Kong 4 major trails (namely MacLehose Trail, Wilson Trail, Hong Kong Trail, and Lantau Trail). It basically divided into 4 trail sections and 3 of them are connected with public transportation by MTR and ferries. The route to be done on foot is approximately 146km.

The 2020 version of 4TUL was a 189km One Go challenge. It ended up with almost 30 participants who attempted the challenge and most of them succeeded.

2021 4TUL Ultra race was a series of trail running races based on the original 4TUL concepts. Besides the original 189km One Go challenge, there were also races from 1 section to 4 section in a row and team challenges.

In order to increase the level of challenge, 2023 4TUL Ultra race has a slight modification from the original course. The concepts of the course on Hong Kong 4 major trails remains. It has been extended to 170km running distance with a total of 4 race categories, namely 100M Extreme, 100K Warrior, 50K Rocker, and 25K Speedster (50K stage race).