D100 is a state road in Croatia connecting Porozina ferry port - ferry access to Brestova on the mainland (via Jadrolinija)[1] (D402) and D101 state road to Cres and Mali Lošinj.

The D100 road is carried between Cres and Lošinj islands via a swing bridge in Osor across a 12 m (39 ft) wide strait.

[3] The road, as well as all other state roads in Croatia, is managed and maintained by Hrvatske ceste, a state-owned company.

[4] Traffic is regularly counted and reported by Hrvatske ceste, operator of the road.

[5] Substantial variations between annual (AADT) and summer (ASDT) traffic volumes are attributed to the road carrying substantial tourist traffic along Cres and Lošinj.