Ballantrae's beach is not a bucket-and-spade beach, and it is worth saying so plainly before anyone drives down with buckets. It is shingle with patches of sand, backed by the village and the A77. Its glory is something else entirely.
The spit
The River Stinchar reaches the sea here, and over time it has thrown a long shingle spit across its own mouth, forcing the river to run parallel to the shore behind it before finding a way out. The result is a brackish lagoon trapped between the spit and the land — a habitat that is genuinely uncommon, and the reason this unremarkable-looking beach is managed as a nature reserve.
It is a strange and rather beautiful piece of ground: a mile of pale stones, the river on one side and the open firth on the other, with Ailsa Craig offshore and the hills of Kintyre beyond on a clear day. Almost everyone on the A77 drives past without knowing it is there.
The birds
The spit and the lagoon draw waders, wildfowl, gulls and, in season, terns, which nest directly on the shingle. This matters practically: tern and other ground-nesting birds' eggs sit in scrapes on open stones and are effectively invisible until you are standing on them.
So, through the spring and summer breeding season: keep dogs on leads, stay off any marked or fenced areas, and walk the water's edge rather than the middle of the spit. See wildlife around Girvan.
Practical notes
Free. There is parking and there are toilets at The Vennel car park in the village, which also takes motorhomes — one of the few places locally that does.
The shingle is hard walking; boots rather than sandals. There are no lifeguards, and the river mouth has currents, so this is not a swimming beach.
The village has a shop and the King's Arms. Ardstinchar Castle stands ruined above the bridge, and this is the start of the coastal path stage to Lendalfoot. Twelve minutes south of Girvan — see Ballantrae.