The A40 crosses Pembrokeshire from the border with Carmarthenshire westwards to Haverfordwest, then northwards to Fishguard. The A477 from St. Clears to Pembroke Dock and the Cleddau Bridge carries the A477 across the Cleddau Estuary. The A478 traverses eastern Pembrokeshire from Tenby in the south to Cardigan, Ceredigion in the north. The A487 is the other major route, running northwest from Haverfordwest to St Davids, then northeast following the coast, through Fishguard and Newport, to the boundary with Ceredigion at Cardigan.
The main towns in the county are covered by regular bus and train services, and many villages by local bus services, or community or education transport.
Pembrokeshire is served by rail via the West Wales Lines from Swansea. Direct trains from Milford Haven run to Manchester Piccadilly. Branch lines terminate at Pembroke Dock, Milford Haven and Fishguard, linking with ferries to Ireland from Pembroke Dock and Fishguard. Seasonal ferry services operate from Tenby to Caldey Island, from St Justinians (St Davids) to Ramsey Island and Grassholm Island, and from Martin's Haven to Skomer Island. Haverfordwest (Withybush) Airport provides general aviation services.