The polo ball: small, hard, fast, and not quite the same everywhere.

The field ball by rulebook

The HPA says Part 1 of its rules aligns very closely with the AAP and USPA rules, but the ball weight is one place where it does not match the USPA's 2024 book: the two ranges overlap only between 4.25 and 4.5 ounces. A ball at the light end of the USPA range would be under the HPA minimum. The USPA revises its rules each year and its 2026 book was not reviewed for this site, so check the current edition.

Other sources on weight

Secondary sources give other figures. Wikipedia gives 99 to 130 g, EBSCO gives about 4 oz (113 g), and a search summary of Dimensions.com gives 3.5 to 4.5 oz, which we could not confirm. The rulebooks are the primary sources. One August 2026 article on Sporting Road refers to a "10-ounce ball", well above either rulebook's maximum, which looks like an error in that article.

What field balls are made of

Neither rulebook, as read for this site, specifies the material. The other sources describe it differently:

• Wikipedia says modern outdoor balls are high-impact plastic, introduced in the 1970s. It says earlier balls were bamboo, leather-covered cork, hard rubber or willow root, and that early British play used a white-painted, leather-covered cricket ball.
• Krenkerup Polo also says modern balls are high-impact plastic and treats bamboo and willow root balls as historical.
• The St. Moritz Snow Polo World Cup programme (2023) calls the grass ball a small white composite ball.
• EBSCO describes the outdoor ball as bamboo or willow root, about 3.25 in (8.3 cm) across, which conflicts with the sources above on material.
• PARI (2023) reports that Argentine fibreglass balls are popular in India.

How fast it travels

NOCSAE's ND055 eye-protection standard records ball speeds sometimes above 90 mph off an offside forehand, from measurements taken in January 2001. Its test uses a polo ball that meets polo specifications and is approved by the USPA, with a new ball for each model tested. The South African Polo Association's guide speaks of balls travelling at nearly 100 mph. That speed is why helmet and eye-protection rules exist; see helmets and eye and face protection.

Balls in the rules of play

• Buried or damaged ball. Under the HPA's 2026 rules (Part 1 Rule 19), if the ball is buried or trodden in so it cannot be moved, the umpire restarts with a throw-in. A damaged ball is replaced, and a goal counts if the larger part of the ball went through before the whistle.
• Ball stuck in a goal post. HPA 2026 Rule 7c: play continues as if the ball had been hit over the back line, so no goal.
• New ball after a ball goes over the end line. Under the USPA's 2024 Rule 9b, the goal judge places a new ball within one foot of where it crossed, no nearer than 5 yards to the posts or side boards. For a hit-in after the attackers hit the ball behind, the HPA's 2026 Rule 14 places it at least 4 yards from the posts.
• Supply. The HPA's 2026 Annex G gives goal judges a bag or box of balls and tells them to watch for players hitting balls between chukkas and for umpires refilling their ball bags.

Arena balls

The HPA's Arena Polo Hub says the arena ball is larger than the outdoor ball. We found no current HPA or USPA arena rulebook figures for it, so the details below come from secondary sources:

• Wikipedia describes a leather-covered, air-inflated ball, larger and softer than the outdoor ball, with a circumference of 32 to 38 cm, a weight of 170 to 182 g, and a bounce test in which a ball dropped from 2.7 m should rebound 140 to 160 cm.
• EBSCO describes inflated leather, 4.5 in (11.4 cm) in diameter and 6 oz (170 g).
• Topend Sports compares it to a mini soccer ball.

The St. Moritz programme says arena and snow polo both use larger orange balls for visibility, which does not match the leather ball the other sources describe.

Snow and beach balls

No official rulebook diameter or weight was found for either.

• Snow. The St. Moritz programme (2023), from the organiser of the Snow Polo World Cup, says snow balls are larger and orange for visibility, and rigid, smooth and air-filled. Blue News (January 2025) reports that an Italian company designed the larger snow ball, which has two air chambers. Wikipedia says snow polo usually uses a bright, light plastic ball, and EBSCO says snow balls are brightly coloured to stand out.
• Beach. Wikipedia describes an inflated leather or rubber ball at least 12.5 in in circumference. EBSCO says beach polo uses a plastic ball. The two disagree.

The arena and snow gear page covers the other kit differences in those formats.

Ball specifications can change between rulebook editions. Check the current rules of your governing body and tournament for the ball in use.