There is a UK company which grows Wasabi - https://shkspr.mobi/blog/2012/10/fresh-wasabi-in-the-uk/ - absolutely delicious. Bit of a pain to ship and keep fresh, but well worth it.

I've also found a place which imports it from Japan and the USA - https://shkspr.mobi/blog/2012/12/more-fresh-wasabi-in-the-uk... - which may be closer to where you are in the world.