There are several ways how to get to Jáchymov. Anyway, best option is to take a plane to Václav Havel airport in Prague.
Hire a car directly at the airport. Jáchymov is about 2 hours-lasting journey from Prague.By bus
There is a comfortable bus service Student Agency going from Václav Havel airport to Karlovy Vary. You can book and pay the bus ticket in advance through their web pages. The shuttle from Karlovy Vary to Jáchymov will be operated at least twice a day on September 3 and also back on September 5 and 8. The detailed information will be posted later. Please, if you want to use this option indicate it during your registration in the web form.