Caernarfon Castle (also spelled Caernarvon - completed in about 1330) is one of the more magnificent castles visited on our tour of the British Isles. Its coastal location adds to its charm (the site was clearly chosen for its strategic location), and you can see that both the inlet and the bay would add to its defenses.
The castle was well-preserved (apparently some restoration work has been done), and it was possible to get some great photographs from across the inlet. With fishing boats and yachts in the foreground, the view across the water to the castle was a photographer's dream. Pity that we could not have spent longer there to get pictures in different lighting.
I remember reading that Prince Charles was invested there, and it was interesting see the sight of his investment. (Not that I am a loyal Royalist; it's just that there is a family connection to North Wales.)
Parking was easy; as you can see, there is a car park beside the castle (pity about that... convenient, but doesn't do much for the photos!) We parked a block or two away and explored some of the shops around the castle. (Had to get a Welsh souvenir... my mother was Welsh.) It was certainly worth making the effort to visit this castle, but much more than the hour or so that we had is needed to truly appreciate its beauty.
Spend time to explore the inside of the castle, but also make sure that you take the opportunity to get photographs from across the water. It's worth the effort.