Istria 100 by UTMB is a trail running event that takes place over 1–4 April 2027 at Umag, Istria, Croatia. It is part of the UTMB World Series. It offers races in the UTMB World Series 100M, 100K, 50K and 20K categories. The event is organised by UTMB Group. Visit the official event website for full details and registration.

Listing only: ToughASIA is not the organiser of this event. Please refer to the official event website for registration and details. Organisers may contact us to update or remove this listing.