Caernarfon postcodes: LL54 and LL55
Which postcode covers which part of town and which villages, plus the postcodes people look up most.
Caernarfon is the post town for two postcode districts, LL55 and LL54. Between them they cover the town itself and a wide area of villages, from Llanberis and Beddgelert in the mountains to Trefor on the Llŷn coast, which is why so many addresses that are miles from town still end in "Caernarfon".
LL55: Caernarfon town and the villages towards Eryri
| Sector | Main places |
|---|---|
| LL55 1 | Caernarfon town (including Victoria Dock, Pavilion Hill and Bethel Road) and Bethel |
| LL55 2 | Caernarfon town (including the castle, Castle Square, Hendre and Segontium), Bontnewydd and Caeathro |
| LL55 3 | Deiniolen, Penisarwaun, Brynrefail, Clwt-y-bont and Dinorwig |
| LL55 4 | Llanberis, Llanrug, Waunfawr, Cwm-y-glo, Nant Peris, Beddgelert and Nant Gwynant |
LL54: villages south of Caernarfon
| Sector | Main places |
|---|---|
| LL54 5 | Llanfaglan, Dinas, Llandwrog, Dinas Dinlle, Saron, Pontllyfni, Clynnog Fawr, Trefor and Llanaelhaearn |
| LL54 6 | Penygroes, Talysarn, Llanllyfni, Nantlle and Nebo |
| LL54 7 | Groeslon, Carmel, Rhostryfan and Rhosgadfan |
Postcode sectors do not follow village boundaries exactly, so a few edge-of-village addresses fall into a neighbouring sector. Y Felinheli, between Caernarfon and Bangor, is in LL56 (post town Y Felinheli), not a Caernarfon postcode.
Useful postcodes in Caernarfon
| Place | Postcode |
|---|---|
| Caernarfon Castle | LL55 2AY |
| Castle Square (Y Maes) | LL55 2NN |
| Galeri and Victoria Dock | LL55 1SQ |
| Segontium Roman Fort | LL55 2LN |
| Gwynedd Council offices | LL55 1SH |
| Caernarfon Royal Town Council and library, Pavilion Hill | LL55 1AS |
| Byw'n Iach Arfon leisure centre and Ysgol Syr Hugh Owen | LL55 1HW |
| Caergylchu recycling centre, Cibyn | LL55 2BD |
| Penllyn car park | LL55 1NN |
| Balaclafa long-stay car park | LL55 1AR |
More car park postcodes are in our getting here and parking guide.
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Local information Living in Caernarfon
Postcode coverage based on Royal Mail district data as published, checked October 2026. To confirm an exact address, use the Royal Mail postcode finder.
