Taiwan can't, but didn't I hear about one of their neighbours doing such a thing? Oh yeah... Australia. Funnily enough, the contract for the next-gen fleet they were building with France got cancelled and re-made with the US + UK, which is an interesting coincidence considering who the largest non-Chinese force in that region is.

About your last clause: <<which is an interesting coincidence considering who the largest non-Chinese force in that region is>>

I assume you are referring to the United States. Is the US military based in East Asia larger than Japan Self-Defence Forces? Honestly, I'm not sure. JSDF is much larger than most people realize. And to be clear, the UK has almost no presence in East Asia now. Every few years, they have a global tour, but nothing else.

And regarding the Australia submarine deal, France would only build diesel-electric subs. US+UK promise to help Australia to build nuclear subs. To me, that is the #1 reason why Australia cancelled the France deal. I am sure they negotiated for months behind the scenes to upgrade to nuclear. When rejected, they announced the Ausuk deal.

In terms of largest number of people, sure the JSDF might be larger, but in terms of raw fire power, I don't think anything comes close to America. And it's not like America has just one or two bases in the region to project from.

I agree with your comment about "power projection". Yes, nothing compares to US in APAC. That said, I do think the technical prowess of JSDF Navy is under-rated. They have some very advanced equipment and have excellent integration with US forces. However, Mainland China is a serious counter-threat to US regional military dominance. Honestly, it is weird that China is investing so much in aircraft carriers. After the 2005 Swedish HSMS Gotland training incidents with a new US carrier, it was demonstrated that the era of _effective_ invicibility for carrier groups is over. It was already true, but less obvious, during the Falklands War with the Agentine carrier that was kept out of action by the mere _threat_ of highly advanced UK subs. Asymmetric warfare is the future. Mainland China should be investing more in asymmetric warfare (crouching tiger / samurai type of stuff: air/ocean/undersea drones, submarines, hypersonic missiles, etc.)

I did some Google searches. Taiwan has been trying for years to buy more modern subs. All attempts fails. They are now developing a domestic solution. Read more here: https://en.wikipedia.org/wiki/Indigenous_Defense_Submarine