This particularly stunning Portugal Cave (sometimes known a the cave beach Algarve) is located along the coast next to Benagil Beach (Praia de Benagil), in the Algarve Portugal. The closest cities are is Portimao, Albufeira, Carvoeiro and Lagoa.
You can rent Kayaks or Paddleboards for about the same price as a sea boat tour if you want. Its a cool idea but I think for the price it is so much better to take the tour as you will see more of the Algarve coastline.
Take one of the Benagil Cave Boat Tours. This is the best way to visit the Benagil Caves. It is the safest and best option as you will visit other caves in the area on the boat trips.
Check out this tour:
https://www.viator.com/tours/Lagos/Boat-Trip-to-Benagil-Caves/d23572-272952P2?pid=P00012552&uid=U00356192&mcid=58086