There are some threads about Xiao Liuqiu already, but most of them are quite outdated. Let’s rename this thread Xiao Liuqiu 2021, and I will post some links to older threads below.
Will also merge your thread about getting from Kenting to Donggang here as well.
Older threads
[Year of first post]
[2006] The Xiaoliuqiu (Little Liuqiu) thread
[2008] Xiǎo Liúqiú
[2009] Xiao Liuqiu (island off the coast of Kaohsiung)
[2015] Pingtung County’s "Siao liou ciou" Island [Little Okinawa?] (小琉球)
I thought there were way more threads here, because Little Liuqiu has become quite popular in recent years.
Also check out the Freedive Nomad blog. He has great introductions to the island and the freediving there.