Asia is mentioned particularly in Missee Lee, which is set in China. Singapore is also mentioned.
When Captain Flint sees the narrow high bridge over the gorge he says Bit of an engineer, old Lee, if he did that .... I've seen something like it in the Himalayas (ML17).
Captain Flint had come a nasty bump in a ship's gig against the coast of Java (the patch) didn't leak a drop .... Shouldn't be here if it had (SD7).
Expeditions to Kanchenjunga in the Himalayas had been much in the news while Ransome was writing Swallowdale.
John says on the top of Kanchenjunga that if they went beyond the Isle of Man they would come to Ireland .... America.... the Pacific and China .... all Asia and then all Europe (SD27).
In Coot Club Mrs Barrable is in the Teasel, but her brother Richard had to go off to London to paint portraits of some important Indians (CC1,5).
Books on the Dutch East Indies in the study (PM19).