| Sg. Indef. | regnskógur |
| Sg. Def. | regnskógurinn |
| Pl. Indef. | regnskógar |
| Pl. Def. | regnskógarnir |
| Sg. Indef. | regnskógar |
| Sg. Def. | regnskógarins |
| Pl. Indef. | regnskóga |
| Pl. Def. | regnskóganna |
| Sg. Indef. | regnskógi |
| Sg. Def. | regnskóginum |
| Pl. Indef. | regnskógum |
| Pl. Def. | regnskógunum |
| Sg. Indef. | regnskóg |
| Sg. Def. | regnskóginn |
| Pl. Indef. | regnskóga |
| Pl. Def. | regnskógana |