Whether showing in pleasure classes or grand prix dressage, appropriate well-fitting attire and tack always makes the best impression. As in the astride world, side saddle attire depends upon the discipline ridden. The basic rule of thumb is to add an apron to the outfit worn by astride riders. For more on historical outfits, see the Historical Attire page.
Formal hunt attire is based on a long history of hunt field tradition. It includes a formal habit (black or navy, in a conservative cut), hunt vest, brown gloves, hunt whip, sandwich case (also called a hunt canteen) and other appointments detailed in USEF HU129 and HU130 and also Some Notes On Appointments. Each of these items have a use in the hunt field. For example, a stock tie becomes an emergency bandage, while rain gloves are kept handy so they can be pulled on quickly over wet leather gloves. Traditionally, a black top hat and veil are worn with this attire. However, as of April 2012, USEF rules mandate protective headgear at all times when mounted at shows run under its rules. Rules permitting other headgear also explicitly do not penalize helmets. ISSO strongly encourages helmet use at all times while mounted.
Informal hunt seat attire displays the same range of colors worn by astride riders. Some aside riders prefer the variety of tweeds, browns, and other colors over the uniformity of the formal attire. Informal attire is expected to be neat, tidy, and workman like, and horses are still braided if appropriate for the venue. However, other appointments such as the whip and sandwich case are not required (except for brown leather gloves, which are still called for). Collared shirts and ties are frequently seen in the UK, in the US, ratcatchers are more common. Instead of a top hat, a bowler is often worn (with or without veil depending on your country and local style), but a safety helmet is always appropriate. ISSO strongly encourages helmet use at all times while mounted.
Dressage riders are the exception to the “just add an apron that matches your breeches” rule. Instead of white, the aside dressage rider wears black or navy. Yes, the same habit can do double duty as formal hunt seat and dressage! However, hunt appointments such as the sandwich case and rain gloves are not appropriate to go down the center line. From the waist up, wear the same clothing you would astride - including the recently-mandated (in the US) helmet.
Western riders usually do not refer back to history to choose their attire as the modern fashions constantly change, especially in the show ring. A western styled apron, for example made of leather, or wool ornamented with conchos, is added to the current style. Chaps are not worn under the apron, as they are too bulky.
Saddleseat and gaited riders dress according to show ring fashion, must as their Western counterparts do. The aprons are longer than the hunter apron, and in less formal classes, a contrasting day coat is often worn.
Concours d'Elegance classes are judged on the overall picture of elegance the rider and horse present. The class may either be costume or not, and should be specified in the class title or description. In either case, detailed inspection of tack and attire is not required, and fancy dress (fun/fantasy costumes) are not permitted. Competitors will be asked to walk, trot, and canter. This class is far more common in the UK than elsewhere.
Fun/Fantasy Costume or Fancy Dress are where the imagination kicks in. Fairies, brides, genies, cat-and-mouse, Humpty Dumpty, Dorothy and the Cowardly Lion, mad scientists, dragon slayers, the Frog Prince, mermaids, and countless other creations have entered these classes. The primary requirement is that the costume be safe for horse and rider, and not spook the horse or other horses in the class.