There are many amazing beaches within striking distance but these are our personal favourites-

Porthtowan Beach
The perfect place to enjoy surfing on Cornwall's north shore. Surf/Body boards are available for hire and the life-guards are on patrol throughout the summer months. There is also and excellent beach cafe (The Blue Bar) that serves food/drinks throughout the day. There is a large car park (by Cornwall standards) though it will get busy in high season. The beach is dog friendly in the winter months however it is closed for dogs between Easter day- 1st October.

Porthcurnick Beach
This a dog friendly beach all year round. It's situated on the Roseland (south coast) so it's generally calm and perfect for paddling/swimming with soft sand under foot. We also like it as it is home to the Hidden Hut, an award winning beach side cafe that is famous for its evening alfresco feast nights. For these you must book well in advance as and when the tickets are released but my goodness they are worth it!
Best way to get there is to take the King Harry car ferry across to the Roseland and then on to Phillieigh.

Porth Joke
This is another all year around dog friendly beach, but this time set on the North coast, so great for those body-boarding experts amongst you! It's well off the beaten track, but that's what we like about it! A large sandy beach with a small river running through it and set down from the cliffs so it's generally well sheltered from the wind. There's no insitu lifeguards on watch so you do need to take the normal precautions with young ones, but we've had countless great times here.