Just head to Puerto Mazarron from Mazarron town and it is the first beach you come to with the sign Playa Canina pointing to the right.
From the outside it does not look too inspiring. There is an obstacle blocking the car park for some reason and it is covered in graffiti. Just look for the sign for Playa Canina where there are plenty of places to park on the road.
Beyond the obstacle is a LOT of dog poo unfortunately.
Just walk straight past the poo and the beach itself is clear. At this point our hound was straining to get off her lead and launch herself at the sand.
The sand itself is not great, it is clean but stony. The stones continue down the sea, which was lovely by the way. This beach is on the Mediterranean coast of Murcia so it is lovely and warm, with proper waves and tides.
There are no facilities on this beach. So no toilets or any chiringuitos (beach bars). There were plenty of other happy doggies though and it was really nice seeing ours off the lead chasing her ball into the sea.
If you have a dog in the Murcia area, it is probably worth checking out. You could bring a picnic and make a day of it, or just go for an hour like we did. There are plenty of outdoor places in Puerto Mazarron where you can get a drink or food after your dog has tired themselves out.