Which balls are approved for high-altitude venues such as Johannesburg and Pretoria?

Q: Which balls are approved for high-altitude venues such as Johannesburg and Pretoria?

The 2026 ITF Rules of Tennis (Appendix I) treat play above 1,219 m (4,000 ft) above sea level as high altitude, which covers Johannesburg and Pretoria. Three ball options are approved there: Ball Notes High Altitude ball Pressurised; rebound 122 to 135 cm. Specified only for play above 1,219 m. Type 2 (medium) pressureless Internal pressure no more than 7 kPa (1 psi); must have been acclimatised for 60 days or more at the tournament's altitude. Type 3 (slow) Recommended for high-altitude play on any court surface. Otherwise, ball type is matched to court pace: Type 1 (fast) is intended for slow courts such as most clay; Type 2 (medium) for medium-slow to medium-fast courts such as most acrylic hard courts; Type 3 (slow) for fast courts such as grass. Red, orange and green balls for 10 and under events have their own specifications.

Question

Accepted Answer

The 2026 ITF Rules of Tennis (Appendix I) treat play above 1,219 m (4,000 ft) above sea level as high altitude, which covers Johannesburg and Pretoria. Three ball options are approved there:

Ball	Notes
High Altitude ball	Pressurised; rebound 122 to 135 cm. Specified only for play above 1,219 m.
Type 2 (medium) pressureless	Internal pressure no more than 7 kPa (1 psi); must have been acclimatised for 60 days or more at the tournament's altitude.
Type 3 (slow)	Recommended for high-altitude play on any court surface.

Otherwise, ball type is matched to court pace: Type 1 (fast) is intended for slow courts such as most clay; Type 2 (medium) for medium-slow to medium-fast courts such as most acrylic hard courts; Type 3 (slow) for fast courts such as grass.

Red, orange and green balls for 10 and under events have their own specifications.