The coast near to St Just town has two coves; Porth Nanven in Cot Valley and Priest's cove at Cape Cornwall. Porth Nanven has large round boulders, and sometimes a little sand, Priest's cove is stony, with a small man made swimming pool, and rock pools for exploring at low tide. The sea tends to be rough and seaweedy around this part of the coast, so not usually suitable for swimming.
A few miles south lie the beaches at Sennen and Gwenvor; around 15 minutes by car. Both are stunning golden sand beaches, and popular surfing destinations. At Sennen, surf lessons run all summer, and you can also hire surfboards and wetsuits. Both beaches have lifeguards on duty during the summer season.
A little further south is the popular Porthcurno beach, nestled beneath the famous Minack Theatre.
Other small coves can be discovered along the coast south of Lands End. Nanjizal, Porthchapel and the breathtaking Pednvounder can only be reached on foot, but there is a lane down to Porthgwarra.
Along the north coast of Penwith, the coastal path gives access to a few small coves at low tide, Portheras, Treen, and Veor coves to name a few, before reaching the lovely golden sands of St Ives Bay, Hayle and Gwithian Towans, with it's 3 miles of sand dunes.
It is worth noting that Penwith weather can be very localized, and a sea mist on the North coast may give way to sun in the South! There are webcams at various locations around the coast, best found through a web search, as they come and go. It is also worth keeping an eye on tide times, especially if you are exploring the smaller coves, as many disappear at low tide, and it is possible to get cut off, the waves and currents can be very strong around some parts of the coast.