Safe diving requires training. Not only is the underwater environment hazardous but equipment such as SCUBA can be dangerous to the untrained.

Many diver training organizations exist, throughout the world, offering diver training leading to certification: the issuing of a C-card or qualification card. Reputable dive operators, dive shops and compressor operators refuse to allow uncertified people to dive, hire diving equipment or fill diving cylinders.

A good dive training organisation, such as a dive school based at a dive shop, will always offer courses to the standard of a recognised certification organisation, such as those listed below. Many dive shops in popular holiday locations offer courses that can teach you to dive in a few days, and can be combined with your vacation. Upon completing the course the student is issued a certification card.

Sources of diver training

Many diver training organizations exist:

• Entry-level recreational SCUBA diver training organisations using professonal instructors. Examples of this type are PADI and NAUI
• Entry-level recreational SCUBA diver training organisations using amateur instructors. An example of this type is British Sub Aqua Club
• Technical recreational SCUBA diving organisations. Examples of this type are IANTD and NAUI Tec
• Commercial diver training organisations. Train divers for professional diving using SCUBA, surface supplied diving and saturation diving equipment and techniques.
• National navies and armed forces. Train divers for ship maintenance, salvage and repair, rescue, mine clearance and covert operations using SCUBA and more advanced equipment and techniques.

Location of training lessons

Initial training takes place in three environments:

• Classroom - where material is presented and reviewed
• Pool - where skills are taught and practiced in confined water
• Open Water - where the student demonstrates the skills he or she has learned.

Typically, early open water takes place in a local body of water such as a lake, a flooded quarry or the sea.

Training topics

• Basic diving theory:
  • Diving physics
  • SCUBA Equipment
  • Physiology
  • Diving disorders
  • Diving signals
  • Buddy system

• Basic water skills:
  • Finning
  • Wearing a diving mask
  • Snorkelling
  • Shallow free-diving

• Basic Aqualung skills:
  • Preparing the Aqualung
  • Buddy check
  • Breathing from an Aqualung
  • Buoyancy control using the Buoyancy Compensator and the lungs
  • Ascents and descents
  • Mask clearing and demand valve clearing
  • Air sharing
  • Air sharing ascent

• Basic Rebreather skills:
  • Preparing the Rebreather
  • Buoyancy control using the Rebreather
  • Ascents and descents
  • Mask clearing and mouthpiece draining
  • Bailing out
  • Bail out ascent
  • Diluent flush

• Dive planning skills:
  • Buddy system
  • Use of decompression tables
  • Use of Dive computers
  • Breathing gas requirement calculations
  • Safe dive site selection
  • Precautions for night dives and drift dives

• Dive leading skills:
  • Compass navigation
  • Underwater pilotage
  • Use of surface marker buoys
  • Use of decompression buoys
  • Use of distance lines
  • Use of diving shots
  • Decompression stops

• Rescue techniques:
  • Controlled buoyant lift
  • Towing diver and landing a casualty
  • In water artificial ventilation
  • CPR on land
  • Oxygen first aid on land

• Technical diving techniques:
  • Using Nitrox as a bottom gas
    • Analysing proportion of oxygen in a breathing gas
    • Calculating maximum operating depth of a breathing gas
    • Calculating equivalent air depth of a breathing gas
  • Using Nitrox as a decompression gas
    • Planning accelerated decompression
  • Normoxic Trimix as a bottom gas
  • Hypoxic Trimix as a bottom gas

• Vocational techniques:
  • Cave diving techniques
  • Underwater photography
  • Underwater videography
  • Underwater archaeology
  • Marine life identification
  • Marine biology

• Dive group leading skills:
  • Selecting dive sites using nautical charts
  • Tides and use of tide tables
  • Weather influences and prediction
  • Group rescue management techniques
  • Dive group safety, prevention and supervision
  • Underwater search and recovery skills
  • Underwater survey skills

• Logistical skills:
  • Boat handling and seamanship
  • Boat navigation and position fixing
  • Compressor operation
  • Gas blending
  • Use of group equipment such as diving shots and decompression trapeezes
  • Recompression chamber operation

• Instructor skills:
  • Teaching diving theory
  • Teaching personal diving skills
  • Teaching group diving, safety and rescue skills
  • Teaching boat handling, seamanship and navigation skills
  • Teaching instructing skills