We sailed throughout the night last night, crossing the equator twice as we made our way round the northern side of Isla Isabela. As predicted, it was a bumpy ride, especially once we rounded the top of island and hit the prevailing swell side on.

Everyone survived though and made it to breakfast albeit a bit tired from lack of sleep. The boat had been rolling enough from side to side to make it almost impossible not to be rolled backwards and forwards in your bed.

We were anchored in Tagus Cove and were reading some of the historical graffiti on the cliffs, from the sundeck, while Galapagos penguins and sealions swam around boat. The graffiti is just names of boats and the year that they visited with some being over 100 years ago. Bizarre to think that some might have come for conservation reasons but still scarred the landscape.

The dinghies took us for a dry landing so we could walk to a viewpoint of the still active volcanoes. A Galapagos hawk was flying overhead as we passed by Darwin's Lake - a collapsed cone which created a shallow lake with trapped sea water.

Instead of returning directly to the boat, the dinghy took us up the edge of the cliff for a closer look at the graffiti, sea lions, penguins and the flightless comorants.

After a quick snack, we changed into our snorkelling gear. We were going to retrace the route the dinghy took us earlier but this time we would be in the water. As soon as we were in the water, a green sea turtle and sealion were keeping us company.

We saw heaps more turtles, penguins, sea lions, flightless comorant, chocolate chip starfish, big red starfish, puffer fish, wahoo, harlequin fish, parrot fish, schools of little fish, jellyfish, pacific boxfish and bumphead parrot fish to name a few. It was an incredible variety and very ***********centrate on the 'smaller' stuff when there was 'bigger' stuff around.

Everywhere you looked there seemed to be another turtle, at one point there were two turtles in front of us, one to the left and another to the right. The penguins were crazy, they were chasing little fish at incredible speed. Backwards and forwards, turning around in impossibly small circles - it was hard to keep your eye on them. The flightless cormorants would dive into the water and seemingly casually, start poking around in cracks and crevices looking for food before moving on. Sealions were not looking for food, they were just playing and showing off.

It has to be one of best snorkeling trips ever (despite water being bit cold), everyone was blown away by the amount of marine life we had encountered. It was like being part of TV documentary and there was never a dull moment.

Back on board, we quickly showered and headed up to the sundeck while the boat headed to the nearby island of Fernandina. It wasn't long before we could see whales breaching and blowing in the distance and the captain changed course, to head in their direction. By luck we were suddenly in the middle of half a dozen whales, one Brydes whale and the rest Humpbacks, and one breached just beside the bow of the boat in the same way a dolphin might.

After lunch, we were taken by dinghy to Punta Espinoza for a walk to see the marine iguana colonies. If you've ever seen a picture of marine iguanas lying on top of each other basking in the sun, it's likely the photo came from here. As we walked up from the shore, what we initially thought were rocks, were actually the piles of iguanas; there were hundreds of them.

We walked round the shore side of their nesting area and came across a Galapagos Hawk and some sealions. A mother and her newborn pup seemed to be the focus of the hawk's attention. The pup was equally curious with us and the hawk and ventured within metres of both. Fortunately, the hawk decided against making the pup a meal.

Further round the rocky shoreline was another marine iguana colony but this one seemed to double as a creche - there were dozens of little babies, some basking in the sun and others hiding in the crevices.

We walked further round the coast across the black lava flow specifically see the lava cactus. It's weird seeing a cactus growing in the middle of a sea of lava. There was also a whale skeleton on the lava although this was pieced together by people over time.

The rocky inlets had some green sea turtles and one rock pool had three small sealions in it. Robert decided to put his GoPro at the edge of the pool for some footage, the sealions thought it was a good toy and quickly grabbed it. After a tense 10 minutes, Robert managed to retrieve the camera to the disappointment of the sealions.

Back on the boat, the captain advised it was a shark free zone and anyone wanting to swim around the boat could. The Hawaiian boys, Andrew and Jack, decided the best way to get into the water was off the top of the boat. A few others, also some of the crew, followed afterwards but none as impressively as Andrew with his acrobatic flip.

The sun dropped spectacularly for us just before dinner and afterwards the cloudless night sky brought out thousands of stars. The Milky Way was clearly visible and we spent ages looking at all the constellations.