Shetland is, quite simply, where the Shetland pony comes from — the breed is named for these islands, and ponies have been bred here for centuries, historically for crofting and transport work as much as for children to ride, which shaped their extraordinary hardiness and strength for their size. Buying a Shetland actually bred on Shetland is buying from the true source of the breed.
Reaching the islands means a ferry crossing from the Scottish mainland (or a flight), so this is a genuine expedition for a mainland buyer rather than a casual viewing trip — factor in crossing times, weather-dependent sailings and the cost and logistics of bringing a pony back with you. For island-based families, local breeding knowledge runs deep, and sellers often know a pony's bloodline back several generations.