Vehicles

 are systems crafted by the player that enhance movement in Subnautica.

also can help with deep sea travel. The most basic vehicle is the sea glide.

Glides
Seaglide:

The only glide in the game yet. It is faster than the upgraded fins but slower then a Seamoth. Seaglides don't restore Oxygen. To make one you need a Fabricator. Ingredients are a battery, lubricant, copper wire and titanium. Fragments can be found in Cargo Crates & Wrecks in the Safe Shallows and Kelp Forests. A capability of the Seaglide is the holographic topography (seafloor map) projector and a flashlight. Unlike the flashlight however, it cannot be pointed above water.

exo suits
The P.R.A.W.N Suit is the only exosuit in game. It has a lot of upgrades. You can only put one ion power cell in the suit.

Submarines
Seamoth:

Seamoths are the smallest submersibles with the capability of navigating depth down to 900 Metres below sea level. It's a stable place for oxygen however can get it can be damaged. To repair the Seamoth you need a repair tool or the Cyclops Docking Bay Repair Module when docked in the Cyclops. Upgrades are the 3 Depth Modules (MK1 increases crush depth to 300 Metres, MK2 increases the crush depth to 500 Metres and the MK3 increases crush depth to 900 M), the Internal Storage Module (gives the Seamoth 16 storage slots with each module), the Hull Reinforcement Module (reduces hull damage by 20% with each module and completely negates ambient environment damage), the Engine Efficiency Module (increases engine life by 15% with each module), the Solar Charger Module (charges the Seamoth's Power Cell in the day time when exposed to daylight and above 200 Metres), the Perimeter Defence Module (makes an electric field around the Seamoth), the Torpedo System and Sonar System. The Depth Module MK1 and Internal Storage Module can be found on the Aurora and crafted with the Vehicle Upgrade Console. The Hull Reinforcement Module, the Engine Efficiency Module, the Solar Charger Module, Perimeter Defence Module, the Torpedo System and the Sonar System is crafted at the Vehicle Upgrade Console. The Depth Modules MK2 and MK3 are crafted at the Modification Station after attaining the blueprint for the Vehicle Upgrade Console. Only 4 Upgrade Modules maximum can be installed per Seamoth. Seamoths are powered by power cells, and their ion variants. To build one you need a Mobile Vehicle Bay. The materials needed for a Seamoth are a titanium ingot, 2 glass, lubricant and a power cell (any, even dead ones talk about trolling the law of conservation of mass and energy primarily energy. unless the energy recharges the powercell while fabricating the vehicle. if that;s the case then a fabricator is a make shift charger.)

Cyclops:

These are large submarines that are capable of making a mobile base. Like a seamoth, you can repair by using a repair tool on specific spots with leaks. Repairing leaks will increase the Cyclops's health until it is back up to full. You will need to scan 9 fragments to unlock this. These are: 3 Cyclops Bridge Fragments, 3 Cyclops Engine Fragments, & 3 Cyclops Hull Fragments.