Cape Sounion and Temple of Poseidon Half-Day Trip from Athens. Take your own postcard-perfect snaps of Cape Sounion's Temple of Poseidon on a scenic afternoon trip from Athens. Cape Sounion is only 45 miles (70 kilometers) from Athens, making it the perfect lazy afternoon destination. Book and Save 10% Off Cape Sounion and Temple of Poseidon Half-Day Trip from Athens.