Japanese visitors Yuka and Yoshie Kaminade picked a propitious day to see the sites of Fremantle on Wednesday, grabbing some great holiday snaps of the city’s port shrouded in a rare sea fog.

The tops of cranes disappeared in the pea souper, which formed when warm, moist air from up near Geraldton moved over cooler waters further south, according to the Bureau of Meteorology. “As the air passes over the surface of the water it cools, and water vapour in the air condenses to form fog,” the bureau said.

The fog lasted most of the morning, with people on Port Beach enjoying the Pirates of the Caribbean-like appearance of the STS Leeuwin II. Freo Ports said it didn’t affect their operations.