Currently access is only possible by walking along the rocky shoreline when the tide is fully out. You MUST check locally about the tide as if it comes in, there may be nowhere to escape it given some steep sides up to land there.
The walk is over lots of seaweed too making the walk dangerously slippy in places so proper hiking boots should be worn and great care taken.
The castle sits on private land and under no cicumstances are you allowed to enter without the permission of the landowner. No-one is now allowed near the castle as it is in a perilous state and therefore dangerous.