We said farewell to Chiang Mai and arrived in Koh Tao after more than eight hours of travel, which included a two hour flight and three hour ferry ride. Though a bit exhausted, we were excited to finally reach southern Thailand's tropical beaches. 

As we walked along the narrow street that runs parallel to Sairee Beach, we felt something click. We hadn't even seen Koh Tao "with the lights on," but we knew. We decided that the three days we had planned just wouldn't be enough and that we needed to extend the trip by three more days. 

The next morning, the sun was shining, the palm branches rustled in the gentle ocean breeze and we could see the reef through pale turquoise water. We sank our toes into soft, white sand and stared out at the traditional, brightly painted longtail boats floating on the clear-as-glass water. 

Yep, we had made the right decision. 

Our first order of business was to complete an advanced open water certification course. We lucked out with amazing weather and a wonderful instructor, Steve at Simple Life Divers.

We practiced underwater navigation by compass at Mango Bay and played in the buoyancy park next to Koh Tao's popular Twins site. We were blown away by Shark Island, which we caught on a day with remarkable visibility, perfect for gazing at colorful, healthy corals and a plethora of fish. And then we finished things off with a wreck dive (Grace's first), going down to 100 feet! 

After five dives in two days, we were advanced open water divers! ...Just in time for a storm to roll in, churning up sand and washing trash out into the water, making for horrible dive conditions. 

Had we made the right decision? We didn't dwell too much on that question since it didn't matter - we found out that the water was so rough that ferries were cancelled for a few days. So, we hunkered down with thai food and our laptops to do some planning.

We also rented another motorbike and rode up some verrry steep hills to check out a few of the island's viewpoints. Although the inclement weather meant a lot of haze and sh*tty photos, we always appreciate seeing beautiful places from different vantage points. 

Seven days in Koh Tao had gone by in a blink and before we knew it, we were leaving one island but heading for more... next up, our first-ever liveaboard dive trip through the Similan and Surin Islands.