Basic snorkel equipment consists of the following:

• Mask - to enable you to look under water
• Snorkel - to enable you to breathe whilst looking under water
• Fins - to propel you through the water
• Weights - to give you negative buoyancy (help you go down!)

Additional and essential equipment required for SCUBA diving:

• Buoyancy Control Device (BCD) or STAB jacket - this enables you to control your buoyancy
• Cylinder or bottle - this contains your breathing air, 20% oxygen + 80% nitrogen = normal breathing air and is attached to your BCD
• Regulators - these are the bits that you breathe from consisting of a 1st stage (attached to your cylinder), a 2nd stage (the bit you stick in your mouth), a set of gauges (to measure air content and depth) and an octopus (also called alternate air source)

• Wetsuit - made from neoprene to keep you reasonably warm but wet
• Hood - made from neoprene to keep your head warm
• Gloves - made from either neoprene or rubber material to keep your hands warm
• Drysuit - to keep you dry, usually made from either neoprene or tri-laminate materials
• Undersuit - to keep you warm in your drysuit
• SMB - or Surface Marker Buoy is an inflatable blob to tow during your dive - shows everyone where you are
• DSMB - or Delayed Surface Marker Buoy is similar to SMB but is normally deployed at the end of a dive to mark where you will surface
• Knife - can be very useful in case of entanglement
• Dive computer - to help with working out dive times, depth, decompression stop requirements and a lot of other stuff