| Ducin | |
| Pushpin Map: | Romania |
| Subdivision Type1: | Country |
| Subdivision Name1: | Romania |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Caraș-Severin County |
| Length: | 13km (08miles) |
| Mouth: | Nera |
| Mouth Coordinates: | 44.8486°N 21.9158°W |
| Basin Size: | 23km2 |
The Ducin is a right tributary of the river Nera in Romania. It flows into the Nera near Bârz. Its length is 13km (08miles) and its basin size is 23km2.