I cannot stress enough how vital it is to not book this trip before you arrive in Vietnam. Not only are you restricting your dates, you’re also costing yourself a lot of money. Instead of booking a trip online that will pick you up from Hanoi and cost you at least 100$, book yourself a night or two on Cat Ba Island.
When you’re in Hanoi you can buy a bus-boat-bus ticket to Cat Ba Island from literally any of the hundreds of tour operators in the city. Its takes around 4 hours to get to the Island and is a relatively pain free journey. Once on the island you can get on the hunt for your day trip around Halong Bay. Alternatively, you can book a 2 day/1night trip or a 3 day/2night trip around the bay.
Once on Cat Ba Island, I paid $14 for a trip which included a pick up from a local office and drop of at the boat port. The boat which took us was spacious and run by very friendly staff. There was ample room on the boat which also had an upstairs deck which was nice as it gave the smokers somewhere to escape to. The boat sailed around Lan Ha and Halong bay for a few hours before docking at some caves for us to spend the best part of an hour kayaking around. In our case there was a massive thunder storm, which made the adventure even more fun.
Upon getting back on the boat and drying off we were served a lunch fit for a queen. Chicken, fish, veggies, chips, rice, spring rolls and scrambled eggs were laid out for us to feast upon as we continued sailing around these idyllic islands.
The next stop was near a small beach where, as tourists do, we all climbed to the highest point of the boat and bombed into the water creating the biggest splash and loudest noise that we could. We were given around half an hour to swim in the sea before once again returning to the boat.
The third and final stop of the day was at monkey island. Now, I massively disapprove of how a lot of tourists treat these monkeys. You often see them swinging bananas around in front of their faces and then wondering why a monkey bites them or takes a dump on their head. Oh, I wonder? However, as we visited when there was torrential rain, leaving us tourists hiding in the bar and the monkeys hiding in the trees; so it all seemed to work out perfectly. The trip back to shore was short but sweet and had us back at Cat Ba Island for around 5pm. An 8-9-hour day for $14, as opposed to the $100+ days you see online.