I often do Discover Scuba Diving (PADI) on the House Reef in front of my diving center. There are no 'rules' involving a pool session.
If done through PADI there are some basic requirements:
Program Standards:
Depth: Confined Water — 6 metres/20 feet.
Open Water — 12 metres/40 feet.
Diver Prerequisites: 10 years old
Equipment: Mask, fins, scuba cylinder, buoyancy control device with low-pressure inflator, regulator and submersible pressure gauge.
Instructor Rating:
Confined Water — Divemaster who is a Discover Scuba Diving (DSD) Leader.
Open Water — Instructor
Knowledge Development
Conduct a knowledge development session or briefing that covers:
• Breathing rules and equalization techniques
• Equipment purpose and use
• Hand signals
• Regulator and mask clearing techniques
• Respect for aquatic life (if appropriate)
• Importance of watching and staying close to instructor
• Limitations of the program and value of further
training
Confined Water
• Conduct the briefing (see Section Two - Knowledge Development)
• Help participants with their equipment.
• For a pool experience, have participants practice BCD inflation and deflation at the surface in shallow water.
• For confined open water, have participants meet Skill Performance Requirements.
• Supervise participants as they swim around underwater in shallow water. When comfortable, take participants to deeper water as appropriate while monitoring comfort and air consumption.
• Conduct a debriefing and encourage participants to move on to a PADI certification course.
Skill Performance Requirements
Have participants practice the following skills in shallow water:
• Breathing underwater
• Regulator clearing
• Regulator recovery
• Mask clearing
• Equalization techniques
• Inflate and deflate a BCD at the surface
Open Water (optional)
An instructor:
• Conducts Section Two - Knowledge Development.
• Conducts the Skill Performance Requirements (see Section
Three - Confined Water).
• Guides participants on a tour of the dive site while
monitoring comfort and air consumption.