SSI (Scuba Schools International) is an organization that teaches the skills involved in scuba diving and freediving.
There are following SSI freediving certification levels:
| Freediving Level 1 | Freediving Level 2 | Freediving Level 3 | |
| Prerequisit (age) | 12 years | 15 years | 18 years |
| Prerequisit (swim) | 100 m | 100 m | 400m |
| Prerequisit (course) | Level 1 | Level 2 | |
| Prerequisit (sessions) | 6 | 30 | |
| Requirement (STA) | 2:30 min | 3:30 min | |
| Requirement (DYN) | 30 m | 45 m | 75 m |
| Requirement (CWT) | 10 m | 20 m | 30 m |
| Maximum depth | 20 m | 30 m | 40 m |
| Confined Water Sessions | 2+ | 2+ | 2+ |
| Open Water Sessions | 2+ | 4+ | 5+ |
| Suggested Duration | 16 - 20 | 24 - 30 | 30 - 35 |
| Theoretical exam | yes | yes | yes |
Next to SSI freediving certification levels there are also other freediving certifications available from AIDA, PADI or CMAS.
Sources:
https://www.divessi.com/info/en-IC/freediving-level-1-172.html (Retrieved 02.04.2019)
https://www.divessi.com/info/en-IC/freediving-level-2-160.html (Retrieved 02.04.2019)
https://www.divessi.com/info/en-IC/freediving-level-3-160.html (Retrieved 02.04.2019)