I’m tingling with excitement as Spoilsport motors overnight from Cairns to arrive in the Ribbon Reefs, in time for a dive in spectacular Challenger Bay. It’s winter in Australia, and the water temps are a chilly 75 degrees; the boat is more than 100 miles from the nearest port, and despite howling 35-mile-per-hour winds, the group of divers is likewise excited. Because after the dive, we will spend the rest of the day with minke whales. Understand that while diving in the Ribbon Reefs is spectacular, this trip is the culmination of all our lifelong dreams of swimming with one of the planet’s most social marine mammals.

Dwarf minke whales make their annual migration to the northern Great Barrier Reef from Antarctica every Australian winter from May to August, with June and July accounting for 90 percent of the sightings. On our trip, we would see an average of eight to 10 minkes every day, and each experience was different.

I put on a 5 mm wetsuit, hooded vest and thermal undersuit. I jump in, grab the line tied off to Spoilsport’s stern — by Australian law, encounters are by snorkel only — and wait for the whales to arrive.

There is one whale more curious than the rest. It’s a young female, about 20 feet long. She makes continual passes at everyone hanging on the line. For two hours she swims around the boat and back to the snorkelers. She comes closer and closer with each pass, until I can see the hairs on her chin. She seems to scrutinize each of us hanging on the line, and even appears to enjoy the motion of the strong waves whipped up by the wind.

Throughout the encounter I try not to move, following Spoilsport’s code of conduct briefing to the letter: Hang onto the line with minimal movement and drift with the boat in the open ocean. The whales are in control of these encounters, and determine everything from how closely they approach to how long they remain near the boat.

“This will probably be the most emotionally rewarding encounter with a large animal underwater you will ever have in your life,” says Dr. Matt Curnock, the James Cook University and CSIRO Minke Whale Project researcher who happens to be on board. “The whales will come very close to check you out,” he said in his first briefing. “Don’t panic. Keep calm and still, and above all, enjoy how very special this amazing encounter is.”

There is no down time. Sunrise wake-up calls before breakfast start with “Wakey-wakey! It’s time for diving!” Every day, we swim with minke whales. With wonderfully prepared meals in between our water activities, the week becomes a routine of eating, diving, eating, snorkeling, eating and snorkeling some more — and then more eating to break the “monotony.”

At the end of the trip, I ask Curnock if the minke encounters ever bore him. “After 15 years of research and in-water interactions with these whales, when they approach closely and look into my eyes, I still find my heart thumping.” I’ll have to return and find out for myself.

Read more in our Ultimate Diver's Guide to Live-Aboards and find out more about Spoilsport and other live-aboards.