| Country: | HRV |
| Type: | D |
| Route: | 100 |
| Length Km: | 81.0 |
| Length Round: | 1 |
| Terminus A: | Porozina ferry port, island of Cres (ferry link to the mainland) |
| Junction: | D101 to Merag ferry port (ferry link to island of Krk) |
| Terminus B: | Mali Lošinj |
| Counties: | Primorje-Gorski Kotar |
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 12m (39feet) wide strait.[2] The road is 81.0 km long.[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.
| D100 traffic volume | |||||||||
| align=center bgcolor=00c0f0 | Road | align=center bgcolor=00c0f0 | Counting site | align=center bgcolor=00c0f0 | AADT | align=center bgcolor=00c0f0 | ASDT | align=center bgcolor=00c0f0 | Notes |
| D100 | 4001 Predošćica | align=center | 978 | align=center | 3,122 | Between L58084 and D101 junctions. | |||
| D100 | 4003 Ćunski | align=center | 2,166 | align=center | 4,383 | Between L58115 and Ž5157 junctions. |