Subnautica: Below Zero is a very short game, but that is because it is not been fully developed yet. It is good to see all the updates that the developers are releasing and I feel that the game will be amazing when it fully releases. I am not expecting the game to be released in the next year or two because the first game took like 5 years to officially release. As of right now, there are only a couple of land areas that are large and take a lot of time to explore. Here is how you get to them.
What do you need to get to the land areas?
You can go to any of the land areas as soon as you get through the prologue of the game. Once you hit open water and Sam sends the Lifepod for you to save the game in, you can go to any of the land areas. The Arctic Spires is very hard to go to right away because there are a ton of creatures you have to go through. Rocket Island is very easy to get to, but you probably want to find the Seaglide to get you there faster. It can be a little scary just swimming there and it will take some time to reach it.
What are the above sea levels?
These areas are very important because they are for story progression. There are a ton of things you need to get in these areas and they will also help in your survival on the planet. I am not going to spoil anything for you but the Arctic Spires is full of monsters that want to kill you so make sure you have the items you need to progress the areas. The Land areas should be explored later on so explore the water areas for items first.
How to get to Arctic Spires
This area is about 300 meters away from where your Lifepod drops. When you walk out the Lifepod door, go right towards the floating ice. Keep going until you get to a split in the giant ice wall. swim a little ways and you will see a small area that you can climb on to. Climb up and there will be 2 ice walls on either side of you and all you have to do is follow the path. It is very easy to find but you probably want to save this area for later.
How to get to Rocket Island
Rocket Island is a little bit harder to get to but you can explore it right away. Once you exit your Lifepod, go to the surface when it is clear of rain or snow. You will see a mountain-like shape in the distance. If you swim towards it, you will start to see some stuff on it. As you get closer, you will see that it is a giant island. It takes a while to get there, but if you get the Seaglide first, it will cut the time to get there by a lot.