To help you to have a "care free" holiday with your dog, the main points are summarised below. There are also a selection of links to help you in planning your journey to Wales and days out.
Before the main holiday season - generally 1st October to the 30th April - there are hardly any restrictions, other than keeping your dog on a lead on promenades and being expected to clean up any "mess". In the Summer dogs are allowed on the beaches outside certain restricted areas - maps illustrating these are on notice boards at beach entrances.
Carmarthenshire: Out of season - "beaches are open along their full length, with no boundaries or restrictions, to dog walkers" - Summer: during the summer months, the beaches are open "to dog walkers along much of their length. Just look out for the signs!" Carmarthenshire's Guide
Ceredigion: Out of season - No restrictions - Summer - "Every beach managed by the Ceredigion County Council provides areas where you can enjoy the company of your pet dog" Ceredigion's Beach Restrictions (pdf) Excluded: Mwnt & Penbryn (Both owned and managed by the National Trust)
Pembrokeshire: Out of season - "All of Pembrokeshire's beaches (over 50) welcome dogs" - Summer - "During the height of summer some of the more popular bathing beaches have dog restricted areas" Excluded: Whitesands and Tenby North.
Gwynedd: Out of season - Dogs can be taken onto all beaches throughout the year - Summer - Some beaches have dog exclusion areas: ·Aberdyfi,·Abermaw, Barmouth, Fairbourne, Llandanwg, Tywyn. Beach Access in Gwynedd
Pembrokeshire Coast National Park has made great efforts to make the Coastal Path more "Dog Friendly" - "The Park Authority are fitting dog gates to many new and replacement stiles on the path and have decreased the number of stiles from 536 in 1995 to the current total of under 100. 40 of those left have ‘dog gates'". Carmarthenshire has no stiles along its length of Coastal Path, but Ceredigion has.
There is a warning about taking your dog on any Coastal Path that you would be wise to heed:
"There is a real possibility that you will come across both wildlife and farm animals in the National Park, so you will need to keep your dog under control. The coast path can also be a dangerous place and an uncontrolled dog may lead to accidents as the path, in some parts, is very close to the cliff edge. The Coastguard advises that owners should keep their dog on a lead; once a dog picks up a scent, that dog has no thought for its safety!"
Pembrokeshire, in particular, has miles of footpaths and bridleways and Carmarthenshire is not far behind, nor is Ceredigion. In the main you are free to roam, but many rights of way cross farmland and it is necessary to keep your dog on a lead if there are sheep or cattle grazing. Dogs are not allowed into the nature reserves or the Pembrokeshire Islands.
Ceredigion's advise is: "Generally you can take the dog along, unless there is a restriction stopping you from doing so." However, certain paths can be restricted at times: "dogs must be kept on a short fixed lead at all times whilst on permissive access routes or areas and that access for dogs may be stopped altogether at certain times of the year"
There are many upland areas worth exploring with your dog - the Preseli Hills are probably the best known, but Teifi Pools are a moorland area remote from civilisation.
Riverside walks that come to mind is the footpath along the Teifi from Cilgerran to Lechryd (you can let your dog off the lead here), the Gwaun Valley and along the Cleddau estuary.
The Forestry Commission has many acres of forest in Ceredigion & Carmarthenshire. There are literally hundreds of accessible footpaths. For example it is possible to combine seeing the Red Kites being fed with a decent lakeside walk at forestry feeding site of Nant y Arian