| Locality | Postal Code |
|---|---|
| Postal/ZIP Codes in Bettna, Flen | 642 |
| Postal/ZIP Codes in Flen, Flen | 642 |
| Postal/ZIP Codes in Hälleforsnäs, Flen | 648 |
| Postal/ZIP Codes in Malmköping, Flen | 642 |
| Postal/ZIP Codes in Mellösa, Flen | 640 31 |
| Postal/ZIP Codes in Sparreholm, Flen | 649 |