I am not sure. As it looks at the moment it is only possible to buy tickets only online here -

https://www.bilesuparadize.lv/en/cus...DgyNS42MC4wLjA.

After buying digital ticket you will have to exchange it to a real whristband at exchange points. You can find exchange points here - https://www.lvrally.com/en/news/tet-...xchange-points