Delos timeline
- 3rd millennium BC
First settlement
Bronze Age settlers occupied the slopes of Mount Kynthos long before the sanctuary rose.
- 9th century BC
Sanctuary of Apollo
Delos emerges as a pan-Hellenic religious centre and the mythic birthplace of Apollo and Artemis.
- 478 BC
Delian League treasury
Athens and its allies stored their common war fund here after the Persian Wars.
- 426-425 BC
Great purification
Athens bans births and deaths on the island and moves every grave to nearby Rheneia.
- 166 BC
Roman free port
Rome declares Delos a duty-free port, and it becomes the Aegean's busiest trading hub.
- 88 & 69 BC
Sacked and abandoned
Forces of Mithridates and then pirates devastate the island, ending its prosperity.
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French excavations begin
The French School at Athens launches the vast dig that uncovered the city visitors walk today.
Excavation History
Systematic excavation began in 1873, when the French School at Athens (École française d'Athènes) launched the vast, decades-long campaign known as the Grande Fouille that continues to this day. Because Delos was abandoned rather than buried by a single catastrophe, archaeologists could trace the plan of an entire ancient city -- streets, cisterns, shops, and multi-storey houses -- rather than isolated monuments. The island reached its commercial and religious peak from the 3rd to the 1st century BC. As Apollo's birthplace it drew pilgrims and lavish offerings from across the Greek world, and under Roman rule it became the Aegean's principal slave market. The geographer Strabo claimed the port could handle tens of thousands of enslaved people in a single day, a scale of human trafficking that funded the merchant mansions still standing on the site. Prosperity ended abruptly: forces of Mithridates VI of Pontus sacked Delos in 88 BC, pirates struck again in 69 BC, and the island slid into an almost total abandonment that, ironically, preserved it.
Key Artifacts
The most famous monument is the Terrace of the Lions, a row of snarling marble lions dedicated by the islanders of Naxos around the late 7th century BC; at least nine once lined the avenue leading to the Sacred Lake, of which five weathered originals survive (now in the on-site museum, with replicas standing guard on the terrace). One stray Delian lion was carried off to guard the gate of the Venetian Arsenal in the 17th century. The Temple of Apollo formed the island's sacred heart, while the House of Dionysus and House of the Dolphins preserve intricate floor mosaics -- one showing the god riding a panther -- that have survived more than two thousand years. The Ancient Theatre seated about 5,500 spectators above the harbour and fed a giant cistern with its rainwater run-off. The now-dried Sacred Lake is the mythological spot where Leto gave birth, marked today by a lone palm. For the widest view, climb Mount Kynthos (113m), the island's summit, for a panorama across the Mykonos channel and the surrounding Cyclades.
When to Visit
Ferry departures: daily at 9 AM, 10 AM, 11 AM from Mykonos Old Port. Return ferries: 12 PM, 1:30 PM, 3 PM -- the last boat is crucial, because miss it and you are stranded on a closed, uninhabited island. Crossing time: 30 minutes each way. Best strategy: take the 9 AM boat and return on the 1:30 PM or 3 PM ferry, giving you 3-4 hours among the ruins in cooler light. Season: April-October only, as winter ferries are suspended. Weather dependent: strong Meltemi winds routinely cancel sailings in mid-summer, so confirm the crossing the morning of your trip rather than assuming it will run.
Admission and Costs
Round-trip ferry: €20-25 per person (book at the Old Port kiosk or online). Site entrance: €12 adults | €6 reduced (students, seniors 65+). Free entry: under 18s, archaeology students, and Greek free-admission days such as 25 March and 28 October. Group guided tours: €80-120 per person (ferry plus guide plus entrance). Private guide: €300-450 for up to 6 people, not including ferry or entrance. There are no ticket machines, shops, or ATMs on the island, so bring the exact fare in cash, plus snacks and 2+ litres of water per person, since nothing beyond the small museum is sold on Delos.
The Case for a Guide
Delos without a guide is an archaeological maze of unmarked foundations baking in the Aegean sun; a guide provides the spatial and mythological orientation that makes the island's extraordinary density of ruins comprehensible and emotionally resonant.
- Apollo's birthplace mythology vs. evidence: The myth holds that Leto gave birth to Apollo and Artemis on this once-floating island after Zeus anchored it; a guide explains what the archaeological record actually corroborates about the site's sacred status from the 9th century BC onward and why that mythology mattered politically to every Greek city-state.
- The Sacred Lake's ritual role: The lake was the mythological birthing spot and the centre of purification rituals for pilgrims; a guide explains that it was drained in 1925 to eliminate malaria-carrying mosquitoes, and points out the surviving palm tree marking where Leto is said to have gripped the trunk during labour.
- Terrace of Lions original count: Only five marble lions survive from the Terrace of the Lions, but a guide explains that the Naxians installed at least nine in the 7th century BC as an offering — the originals now shelter in the Delos Museum while one guards the Arsenal in Venice — and how they scattered over two millennia.
- Roman merchants' quarter with intact mosaics: The House of Dionysus and House of the Dolphins contain floor mosaics that survived 2,000 years; a guide navigates directly to them through the labyrinthine ruins, explains the specific iconography of each panel, and contextualises the extraordinary wealth of the Roman trading families who commissioned them.
- Delos as ancient duty-free port: Rome declared Delos a free port in 166 BC, instantly gutting the rival economy of Rhodes; a guide explains how this single political decision created the ancient world's most concentrated trading hub — with enslaved people changing hands by the thousand — and why the island was violently sacked by Mithridates in 88 BC and abandoned soon after.
Tips for Visitors
Book ferry tickets ahead: summer boats fill up, so reserve the day before at the Old Port office. Arrive at the port by 8:30 AM for the 9 AM ferry -- it leaves on time. Do not miss the return boat: the last ferry is around 3 PM, and a missed connection means a private boat costing €200+. Bring essentials: water (2 litres per person), snacks, sun protection, and comfortable shoes. There are effectively zero facilities on the island -- no food, drinks, shade, or restrooms beyond the small museum block. The site is completely exposed and reaches 35°C+ in summer, so a hat is mandatory. Plan for 3-4 hours of walking on uneven ancient stones. Photography is allowed throughout with no restrictions, and the low morning light rakes beautifully across the Terrace of the Lions.
Frequently Asked Questions
Which months offer the best conditions for a Delos excursion?
May and September are the prime months -- warm enough for the fully exposed archaeological site but without the blistering 35-plus-degree heat of July and August that makes the shadeless ruins exhausting. Ferries only operate April through October, and strong Meltemi winds in mid-summer can cancel crossings without warning, making late spring and early autumn the most reliable choices.
What time of day is best for touring Delos?
Take the earliest boat you can. Ferries leave Mykonos Old Port at roughly 9 AM, 10 AM, and 11 AM, and return at about 12 PM, 1:30 PM, and 3 PM, giving you three to four hours on the island. The 9 AM departure is best: you tour the ruins in cooler morning light and softer shadows before the midday sun bakes the treeless site, and you comfortably catch the 1:30 PM or 3 PM boat back. Because the island closes when the last ferry leaves, there is no sunset visit -- morning is the only sensible strategy.
What is the entrance fee for Delos?
Two separate costs apply. The round-trip ferry from Mykonos runs about €20-25 per person, booked at the Old Port kiosk or online, and site admission is €12 for adults and €6 reduced for students and seniors over 65. Entry is free for under-18s and archaeology students, and on Greece's free-admission days such as 25 March and 28 October. A guided small-group tour that bundles ferry, guide, and entrance typically costs €80-120 per person; there are no ticket machines on the island, so carry the exact fare.
What should visitors know before taking the ferry to Delos?
Book the day before in summer, when boats sell out, and be at the Old Port by 8:30 AM for a 9 AM departure -- the ferry leaves on time and will not wait. The single most important rule is to catch your return boat: the last crossing is around 3 PM, and missing it means chartering a private boat for €200 or more. Bring at least two litres of water per person, snacks, a hat, and sun cover, because the island has no shops, cafés, shade, or restrooms beyond the small museum block.
Why was no one allowed to be born or die on Delos?
To keep Apollo's birthplace ritually pure, ancient Athens forbade both births and deaths on the sacred island. During the great purification of 426-425 BC recorded by the historian Thucydides, every existing grave was dug up and the remains reburied on neighbouring Rheneia, and thereafter anyone close to giving birth or dying was ferried off the island. This taboo is one of Delos's enduring peculiarities: a place revered as the source of life in myth where, by law, no life could legally begin or end.