| Official Name: | Duga Luka |
| Other Name: | Portolungo |
| Settlement Type: | Village |
| Pushpin Map: | Croatia |
| Pushpin Label Position: | right |
| Coordinates: | 45.0481°N 14.1561°W |
| Subdivision Type: | Country |
| Subdivision Type1: | County |
| Subdivision Type2: | Municipality |
| Subdivision Name2: | Labin |
| Area Footnotes: | [1] |
| Area Total Km2: | 1.2 |
| Elevation M: | 30 |
| Population As Of: | 2021 |
| Population Total: | 30 |
| Population Density Km2: | auto |
| Timezone: | CET |
| Timezone Dst: | CEST |
| Utc Offset: | +1 |
| Utc Offset Dst: | +2 |
Duga Luka (Italian: Portolungo; also known as Prtlog)[2] is a village in the Labin-Albona municipality in Istria County, Croatia.[3]
According to the 2021 census, its population was 30. It was 27 in 2011.