There is a small UGCC community on Singapore. There may also be one in Hong Kong but I am not sure.
There was a White faction (anti-Communist Russians and others) presence in China after the Bolshevik Revolution, some of these refugees living in the Manchurian area (Russian influenced area until the Japanese became dominant around 1905) which would have lasted until the Japanese defeat at the end of WW II. Among these anti-communists would be Russian Catholics, a small portion of Russian minority in China. As with the Orthodox the community was centered in the area of Harbin.
After the Japanese defeat, Communist Russia occupied areas of northern China briefly, and began the process of repatriating Soviet citizens, so at this time people were getting out any way they could. The Chinese civil war between the KMT and the Communists resumed, and Manchuria was one of the first areas to fall to the Communists.
By the time the Chinese Civil war ended in 1949, most Whites were gone or were on their way. This was the reason some Russian Catholics and Ukrainian Catholics found themselves in places like Hong Kong and Singapore, and by the way also San Francisco.

This was the same trek Orthodox were making.
The result is that Eastern Catholicism was entirely wiped out of China. Orthodoxy lasted a little longer (due to the fact that it had some native clergy) and was essentially snuffed out in the Great Proletarian Cultural Revolution in the 1960’s.