| Doubtless River | |
| Mouth Location: | Doubtful River |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Length: | 6km (04miles) |
| Source1 Elevation: | 1343m (4,406feet) |
| Mouth Elevation: | 695m (2,280feet) |
The Doubtless River is a river of northern Canterbury, New Zealand. A tributary of the Doubtful River, it rises south of Mount Boscawen and flows southward through the Lake Sumner Forest Park to join that river 2km (01miles) east of Phantom Flat.[1]
The New Zealand Department of Conservation maintains a backcountry hut near the junction of the Doubtless and Doubtful Rivers.[2]