| Round 4 on 2021/10/03 at 11:00 |
| Bo. | 2 | Taflfélag Reykjavíkur e-sveit | Rtg | - | 4 | Skákfélag Sauðárkróks | Rtg | 2½:3½ |
| 1.1 | | | 1672 | - | | | 1846 | 0 - 1 |
| 1.2 | | | 1712 | - | | | 1821 | 1 - 0 |
| 1.3 | | | Fridthjofsdottir Sigurl. Regina |
| 1663 | - | | | 1757 | 0 - 1 |
| 1.4 | | | 1661 | - | | | Steinthorsson Steingrimur |
| 1696 | ½ - ½ |
| 1.5 | | | 1573 | - | | | 1629 | 1 - 0 |
| 1.6 | | | 1654 | - | | | 1566 | 0 - 1 |
| Bo. | 14 | Taflfélag Reykjavíkur f-sveit | Rtg | - | 3 | Skákdeild Breiðabliks d-sveit | Rtg | 4 : 2 |
| 2.1 | | | 1484 | - | | | 1340 | 1 - 0 |
| 2.2 | | | 1540 | - | | | 1326 | 0 - 1 |
| 2.3 | | | 0 | - | | | 1388 | 1 - 0 |
| 2.4 | | | 1467 | - | | | 1202 | 0 - 1 |
| 2.5 | | | 1389 | - | | | 1237 | 1 - 0 |
| 2.6 | | | 1503 | - | | | Eythorsson Engilbert Vidar |
| 1241 | 1 - 0 |
| Bo. | 7 | Skákdeild Breiðabliks c-sveit | Rtg | - | 10 | Vinaskákfélagið b-sveit | Rtg | 4 : 2 |
| 3.1 | | | 1636 | - | | | 1620 | ½ - ½ |
| 3.2 | | | 1569 | - | | | 1397 | 1 - 0 |
| 3.3 | | | Kjartansson Matthias Bjorgvin |
| 1445 | - | | | 1407 | 1 - 0 |
| 3.4 | | | Thorsteinsson Thorsteinn Jakob F |
| 1416 | - | | | 1436 | ½ - ½ |
| 3.5 | | | Gudnyjarson Sigurdur Pall |
| 1438 | - | | | 1372 | 0 - 1 |
| 3.6 | | | 1158 | - | | | 1258 | 1 - 0 |
| Bo. | 13 | Taflfélag Garðabæjar - ung | Rtg | - | 1 | Skákfélagið Goðinn | Rtg | 0 : 6 |
| 4.1 | | | 0 | - | | | 1823 | 0 - 1 |
| 4.2 | | | Fridriksson Gunnlaugur Dan |
| 0 | - | | | 1798 | 0 - 1 |
| 4.3 | | | 0 | - | | | 1801 | 0 - 1 |
| 4.4 | | | Vilhjalmsson Bjarki Freyr |
| 0 | - | | | 1406 | 0 - 1 |
| 4.5 | | | 0 | - | | | 0 | 0 - 1 |
| 4.6 | | | 0 | - | | | 0 | 0 - 1 |
| Bo. | 6 | Dímon | Rtg | - | 5 | Skákfélag Akureyrar d-sveit | Rtg | 2½:3½ |
| 5.1 | | | 1902 | - | | | 1654 | ½ - ½ |
| 5.2 | | | 0 | - | | | 1483 | 0 - 1 |
| 5.3 | | | 0 | - | | | 1529 | 0 - 1 |
| 5.4 | | | 0 | - | | | 1384 | 0 - 1 |
| 5.5 | | | 0 | - | | | 0 | 1 - 0 |
| 5.6 | | | 0 | - | | | 0 | 1 - 0 |
| Bo. | 8 | Taflfélag Vestmannaeyja c-sveit | Rtg | - | 9 | Taflfélag Reykjavíkur g-sveit | Rtg | 3 : 3 |
| 6.1 | | | 1652 | - | | | 0 | 1 - 0 |
| 6.2 | | | 1545 | - | | | 1214 | 0 - 1 |
| 6.3 | | | 0 | - | | | 1333 | 0 - 1 |
| 6.4 | | | 1561 | - | | | Gudmundsson Fridrik Helgi |
| 0 | 1 - 0 |
| 6.5 | | | 0 | - | | | 0 | 0 - 1 |
| 6.6 | | | 1393 | - | | | 0 | 1 - 0 |
| Bo. | 11 | Víkingaklúbburinn c-sveit | Rtg | - | 15 | Skákdeild Fjölnis c-sveit | Rtg | 4½:1½ |
| 7.1 | | | 0 | - | | | Kjartansson Kristofer Halldor |
| 1270 | 1 - 0 |
| 7.2 | | | 1475 | - | | | 0 | 1 - 0 |
| 7.3 | | | 1208 | - | | | 0 | 1 - 0 |
| 7.4 | | | 0 | - | | | 0 | ½ - ½ |
| 7.5 | | | 0 | - | | | 0 | 1 - 0 |
| 7.6 | | | 0 | - | | | B. Berglindardottir Emilia Embla |
| 0 | 0 - 1 |