Plan a trip to a sea or lake that has bio-luminescent plankton that make any movement of the water glow with coloured light. Walk, swim or paddle through the water with your partner and it’s like walking in star light. Each movement creates a wonderful glow show.
For a ‘wow’ romantic trip, book a journey on a new moon when the phenomenon is occurring in a place it does frequently: The Maldives, Mosquito Bay in Puerto Rico, Luminous Lagoon in Jamacia and San Diego. The Gippsland Lakes in Victoria, Australia often have the phenomenon also.
Unfortunately, like the Northern Lights and other natural phenomena, bio-luminescence is never guaranteed to occur when you are there. Try calling some locals before you go to check if it’s occurring and when the best times are.