The string, and the people who keep it going.

Why one pony is never enough

The rules make a string necessary. Under the HPA's 2026 rules (Rule 2.4e), a pony may not play more than 7.5 minutes without a 10-minute break, or more than 15 minutes in total in normal match time. A four- to six-chukka game is longer than that. Meadow Brook Polo Club describes the result: players change ponies after each chukker and may reuse a pony after at least one chukker's rest. Wikipedia says a player needs at least two horses for a match and uses a separate horse for each chukka, sometimes two.

Polo is unusual here. The UK Polocrosse Association points out that in polocrosse, a related but different sport, a player normally uses one horse for a whole tournament unless it is injured.

How big is a string?

Nobody fixes this number, and the sources we found are not firm.

• A search summary of a Museum of Polo page (the page itself could not be opened) describes two or three ponies for low-goal polo, each rested at least a chukka before reuse, four or more for medium goal, and more at the highest levels.
• A Horse Racing Sense article (April 2022) says a tournament player needs at least two ponies, that four is a professional number and five ideal, and puts the top-level maximum at about eight, one per chukka.
• A La Nacion guide (2001, updated 2020) says each player uses 8 to 10 horses per match at the Argentine Open, but no more than 6 in the semifinals and final.
• Meadow Brook Polo Club estimates that a game uses roughly 40 to 50 ponies for its eight players.

None of these could be confirmed from a second source, so treat them as rough descriptions rather than rules. One study gives a sense of the pattern: Wright and Peters (2008) recorded five chukkas per player in their high-goal heart-rate study, consistent with ponies being changed between chukkas.

Junior polo works differently. The Pony Club's 2026 rulebook says its polo is founded on "one player, one pony", so a child can play from 6 to 21 on a single pony, while its Langford, Hipwood, Rocksavage and Gannon sections play matches of two to four chukkas that need two to four ponies per player.

Rules about sharing ponies

• HPA 2026 (Rule 2.4c): at 12 goals and above, a team may not play a pony already played by another team in the same tournament.
• USPA 2024 Outdoor (Rule 5d): no mount may play for more than one team in a USPA Event; the penalty is forfeiture. The USPA revises its rules each year, so check the current book.
• FIP World Polo Championship: the FIP says horses are supplied by the host and pooled among the teams so conditions are equal.

Not owning a string is not a bar to playing. The HPA says its affiliated pony hirers let players take part in matches and tournaments without owning a pony, and a stick-and-ball trial can be arranged to find suitable ones. See getting started.

Changing ponies during a match

Under the HPA's 2026 rules (Rule 1g), pony changes happen in allocated boxes at any of the four corners of the field, or where the club designates with the umpires' agreement, and not in the safety zones between the two 30-yard lines. In hot weather the HPA allows free changes limited to one minute (Rule 2.4s). The AAP's 2026 women's tournament regulations schedule a general change of horses about halfway through each chukker, during neutral play, limited to one minute.

A former groom writing in Horse Network (2020) describes grooms untacking, washing and re-tacking ponies every few minutes during competition as they come off the field. That is a single first-person account.

Exercising a string

Accounts of the daily routine come from individuals and companies rather than rulebooks.

• The same Horse Network groom says grooms exercise ponies in "sets" of three to five, riding one and leading the others at walk, trot and canter for two to three hours a day on a track.
• Fortloc, a polo GPS-tracker maker, says sets are of five or more, a little different from the Horse Network figure. In another article it describes ponies fed by grooms between about 6 and 8 a.m., exercised in the morning, rested through midday heat and worked again after 3 p.m.
• Wikipedia calls leading one horse while riding another "ponying", and says several polo ponies are often exercised at once by one rider this way.

These are single accounts, and the Fortloc ones are from a commercial source; none is confirmed by a second source.

Grooms and petiseros

In Argentine polo the groom is a petisero. Argentina Polo School (May 2025) says the word comes from the Spanish "petiso", a small horse or pony. It lists the job as feeding and cleaning, tack and saddling, support with conditioning and training, spotting injury or illness, and travelling with the ponies to tournaments.

La Nacion (2017, updated 2020) reports that most petiseros working the English season are young Argentines, that players often bring their own, and that the working day typically starts around 5 a.m. and can run into the evening, often seven days a week.

The rules cover grooms too. Under the HPA's 2026 rules, everyone riding at a polo ground, grooms included, must wear approved protective headgear; the helmets page sets out the standards. The HPA Pony Welfare Hub (page dated 27 March 2026) says all yard staff should be trained in disease prevention, hygiene, identification and control, and encourages owners and welfare officers to read the HBLB Codes of Practice. The HPA's Pony Welfare Booklet is published in English and Spanish.

When a pony retires

Under the HPA's 2026 rules (Rule 2.4a), the owner's responsibility includes taking reasonable steps to safeguard a pony's future care when it is passed on to a new owner, especially when it is retired from polo. New Zealand Polo, which follows HPA welfare guidelines, says the same about a pony in a third party's care over winter and into retirement. The Australian Polo Federation's July 2023 rule limits ponies from 1 August of the year they turn 20 to clinics, lessons and stick-and-ball, with one narrow exception set out on the welfare rules page.

No HPA, USPA or AAP retirement programme or retirement-age guidance was found. Some charities work with retiring polo ponies. ReplayPolo, a US nonprofit founded by Brittany Halstead, identifies retiring polo ponies and racehorses, gives them brief re-education and rehomes them, and runs a lesson programme, according to a 2024 Phelps Media Group report; its horses are based at Willow Run South in Lake Worth, Florida.