Lebanon is small — you can drive from the northern border to the southern in about three hours — and almost everything is a day trip from Beirut.
Check your government’s current travel advice first. It distinguishes between regions, and some of what follows carries more restrictive guidance than Beirut does. See is Beirut safe.
Byblos — an hour north
Seven thousand years of continuous occupation in one tell, a Crusader castle built out of Roman columns, the temple of the obelisks, and a small fishing harbour to eat lunch in.
The easiest good day trip from Beirut, reachable by service taxi or bus for very little.
Jeita Grotto and Harissa — half a day, on the same road
Jeita Grotto is a limestone cave system in two galleries — an upper one walked on foot, a lower one crossed by boat on an underground river. It is genuinely one of the great caves of the world and it was a finalist in the New7Wonders of Nature vote.
Check whether it is open; it has closed for extended periods.
Harissa — Our Lady of Lebanon — is a shrine above Jounieh reached by a cable car with a long view over the bay. Both are on the road to Byblos and all three combine into one day.
Baalbek and the Bekaa — a full day
The largest Roman temple complex ever built, on stones weighing 800 tonnes, two hours over the mountains.
Read the advisory for the Bekaa before planning this. With that done, the standard day pairs Baalbek with Anjar — an eighth-century Umayyad city, unique in the region and UNESCO-listed — and a Bekaa winery, usually Ksara or Kefraya, which have been making wine here for over a century and on this land since the Phoenicians.
The Chouf and Beiteddine — a full day
South-east into the mountains, into the Druze heartland.
Beiteddine Palace, built between 1788 and 1818 for Emir Bashir Shihab II, with courtyards, hammams and one of the great Byzantine mosaic collections in the region, assembled from sites across Lebanon.
Deir el Qamar, a beautifully preserved seventeenth-century town below it.
The Chouf Cedar Reserve — the largest protected area in Lebanon, with the biggest surviving stands of Cedrus libani, walking trails and genuine quiet.
Moussa Castle, which is an entirely eccentric one-man project and is much loved locally.
The Qadisha Valley and the Cedars — a long day
The north, and the most beautiful part of the country.
Wadi Qadisha — the Holy Valley — is a deep gorge with monasteries and hermitages cut into the cliffs, occupied by Maronite and other Christian communities since the earliest centuries of the church. It is a UNESCO World Heritage Site, listed jointly with the Forest of the Cedars of God above it.
The Cedars of God — Arz el-Rab — is one of the last surviving old-growth stands of the cedar that is on the Lebanese flag, that built Solomon’s temple and the Phoenician fleets, and that once covered these mountains. A few hundred trees remain, some of them well over a thousand years old.
Bcharre, the town above the valley, is the birthplace of Khalil Gibran and has a museum in a former monastery.
It is a long day and better as an overnight.
Tripoli — an hour and a half north
Lebanon’s second city, with the best-preserved Mamluk architecture outside Cairo — the Citadel of Raymond de Saint-Gilles, the khans, the hammams and the soap souk.
It has carried more restrictive travel advice at various points; check.
Tyre and the south
Tyre (Sour) has a UNESCO Roman site including one of the largest hippodromes in the Roman world, a Crusader-era old town on a peninsula, and the best beach in Lebanon.
The south carries the most restrictive travel advice in the country and the situation has changed repeatedly. Do not plan this trip without current, specific advice.
Batroun — an hour north
A small coastal town with a Phoenician sea wall, good fish restaurants, clean water for swimming, and its own famous lemonade. The easy, low-key option, and where Beirutis go for a Sunday.
Practical
A car with a driver for the day is the standard arrangement and is not expensive. Agree the price, the hours and the route in advance. Your hotel will arrange it.
Service taxis and buses from Charles Helou (north) and Cola (south and the Bekaa) are extremely cheap and entirely usable for Byblos, Batroun and Tripoli.
Organised tours run from Beirut for Baalbek, the Chouf and Qadisha, and are the easiest option for the more complicated ones.
Start early. Roads are slow and there is no shade at any of the archaeological sites.