Ballycastle is one of the very few places where you can board a boat for either Scotland or one of Ireland's offshore islands. The Rathlin Island Ferry runs four times daily to the L-shaped island visible six miles north of the harbour. The crossing takes thirty minutes and is one of the cheaper genuinely adventurous day trips you can make in the British Isles. The Kintyre Express foot-passenger ferry, running April to September on Fridays through Mondays, goes the other way: 90 minutes from Ballycastle harbour to Campbeltown on the Mull of Kintyre, or 60 minutes to Port Ellen on Islay in the Scottish Hebrides. A return ticket in 2023 was 150 pounds. Bikes travel free. For around the price of a London-to-Brussels train ride, you can island-hop between two countries on a small motor cruiser.

Down at the marina, a stone monument near the ferry ticket office commemorates a piece of communications history that does not get enough credit. In 1898, Guglielmo Marconi - then a twenty-four-year-old Italian inventor whose mother Annie Jameson was a daughter of the Dublin whiskey family - set up a wireless station in Ballycastle to send signals to the East Lighthouse on Rathlin Island. It was the world's first commercial wireless telegraph transmission, paid by Lloyd's of London to relay ship sightings. The makeshift antenna mast was the octagonal spire of St Patrick's and St Brigid's Catholic Church on Moyle Road, which had been finished by good luck just that year. A red phone box still stands on the Promenade nearby, a kind of accidental joke about how far telecommunications travelled in the next century.

Three miles east of town rises Fair Head, a wall of dolerite cliffs up to 300 feet high running for three miles along the coast. The rock is the same igneous material as the Giant's Causeway but here it stands in cyclopean organ-pipe columns rather than the famous hexagonal slabs. To rock climbers, Fair Head is something close to sacred. It is the largest single climbing escarpment in Europe and one of the great trad-climbing destinations in the world. Routes are ascended by hand-jamming the vertical cracks or by chimneying up the wider fissures, all using only natural protection. No bolts, no pre-set hardware. The headland is reached by driving Torr Road east from Ballytoy and parking at a small lake; in the middle of that lake is an Iron Age crannog, a man-made island dwelling thousands of years old. Wild goats roam the cliff-tops. Most days, you will see climbers' ropes dropping down those tremendous black columns and pause to wonder what kind of person volunteers to do that for a hobby.

Two days every August, on the Monday and Tuesday closest to the end of the month, the whole town turns into a market. The Ould Lammas Fair has been held in some form here since 1606, originally a sheep and cattle fair tied to the Lammas harvest festival of 1 August. Today it draws around sixty thousand visitors. Two foods are obligatory. Dulse is dried red seaweed sold in twisted paper bags, salty and chewy, an acquired taste that costs almost nothing here and would cost fourteen pounds at a London Japanese restaurant. Yellowman is honeycomb toffee made by foaming sugar with vinegar and baking soda and then breaking it apart with a hammer. An old folk song asks whether you treated your Mary-Anne to the dulse and yellowman at the fair. Most locals can recite it from childhood. Most visitors leave humming it.

Behind the town, the heather-covered mass of Knocklayde Mountain rises to 1,685 feet, crowned by Carn na Truagh, the Cairn of Sorrow, a Neolithic stone mound whose name no one has fully explained. From the summit on a clear day, you can see the whole of Ballycastle, the long sweep of Rathlin Island, the dark slab of Fair Head, and the green hills of Scotland's Mull of Kintyre. Two of the nine Glens of Antrim begin at Knocklayde's foot: Glenshesk to the south, with a quiet lane and forestry tracks leading up to the summit; and Glentaisie, named for the princess Taisie whose wedding turned into a battle when the King of Norway tried to claim her, and lost. The Glens are the Antrim coast's secret. Most tour buses race past them. People who linger here go home rested.

Ballycastle has lost its own castle but the coast around it is studded with ruined fortifications. Three miles west on a limestone headland sits Kinbane Castle, the gnarled two-storey remains of a 1547 MacDonnell fort, ascended by steps cut into the cliff and offering one of the most photogenic coastal views in Northern Ireland. Just beyond the town, Dunaneeny Castle stands on the bluffs north of the harbour, the birthplace of Sorley Boy MacDonnell. East of Ballintoy, Dunseverick Castle clings to a rock above the sea, a place where St Patrick once visited and Cromwellian troops once smashed up. Each of them is free to visit, mostly unsupervised, surrounded by fields and gorse and the steady noise of the Atlantic. None of them are on the famous loop. All of them are worth your time.