Taking a rental car off Chios by ferry depends on four separate things that normally live in four different places: the ferry operator's tariff sheet, the rental contract's cross-border clause, Turkish customs law, and the physical vehicle deck of the vessel. Short answer. To Greek destinations - Piraeus, Lesvos, Psara and Oinousses - putting a Chios rental car on a ferry is possible, but only with the rental company's prior written permission and, in most cases, a purchased Ferry Boat Cover. To Cesme in Turkey the crossing is effectively closed: the ferry company will sell a vehicle ticket, but Turkish customs requires a notarised power of attorney (vekaletname) from the car's registered owner, which is the rental company, and Chios rental firms do not issue one. The ferry ticket exists; the paperwork to legally drive the car off the boat in Turkey does not. A verbal assurance at the rental desk is not the written authorisation the contract requires. Decision table, five routes off Chios. Chios to Cesme in Turkey: operators carrying cars are Erturk Lines with conventional Ro-Ro vessels and Turyol's Chios ferry; car fare 100 EUR one way, verified from Erturk's own price list, and about 110 EUR from a secondary source for Turyol; the contract requires a notarised authorisation from the rental company, per Erturk's own General Rules; practical verdict - effectively impossible, because Chios rental firms do not issue that authorisation. Chios to Piraeus: Blue Star Ferries; car component about 81.50 EUR, a derived figure rather than a quoted car tariff; the contract requires prior written approval plus the Ferry Boat Cover of 20 EUR a day capped at 60 EUR under Autohellas Hertz terms; verdict - possible with written permission and ferry cover, with vehicle space booked well ahead in August. Chios to Lesvos, meaning Mytilene: about 45 to 65 EUR per car, an aggregator estimate; same written permission and ferry cover requirement; verdict - possible with written permission. Chios to Psara: about 20 to 27 EUR on the small local ferry or 39 to 49 EUR on the larger Blue Star vessel, estimates; sailings only one to three days a week; verdict - possible with written permission, planned around the schedule. Chios to Oinousses: about 30 to 38 EUR, estimate, only a few weekly sailings; verdict - possible with written permission. For Lesvos, Psara and Oinousses no operator publishes a standalone car tariff online; those ranges come from ferry-booking aggregators including Ferryhopper, Direct Ferries and Ferryscanner, plus the local Psara operator's price list, and should be treated as budgeting ranges rather than quotes. Why Turkey is effectively closed to a Chios rental car. Three independent requirements stack on top of each other and any single failure ends the trip. First, the rental contract. Autohellas Hertz, which operates rental desks across Greece including the islands, states that across the border rentals are allowed only with the prior written agreement with Autohellas Hertz, and that ferry transportation is allowed only with the prior written approval of Autohellas Hertz and provided that the renter has accepted the Ferry Boat Cover. A company has to agree to an international crossing, not merely a ferry crossing. Second, Turkish customs law. Under Turkish Customs Law No. 4458 and its temporary-import regime a foreign-plated vehicle can enter Turkey, but the driver must have lived outside Turkey for at least 185 days in the preceding year, and a personal vehicle's temporary-import permit is capped at 180 days; for a rented car it cannot run past the rental agreement's own end date. Anti-Smuggling Law No. 5607, Section 3/9, restricts who may drive a foreign-plated car to the registered owner or someone holding explicit legal authorisation from that owner. For a rental car the owner is the leasing company, not the tourist behind the wheel. Third, the paperwork at the port. Arriving at Cesme with a Chios rental car means producing the original registration document, a passport, a Green Card on which the country code TR is not struck through, and a notarised power of attorney from the Greek rental company, certified by a Turkish consulate in Greece or a Turkish notary. Chios's local firms are not in the business of issuing consulate-certified authorisations for a one-day rental. Boarding anyway is the expensive mistake: Greek island rental terms void cover the moment the car leaves the island without consent. What the ferry actually costs with a car. Erturk Lines' published price list for the Cesme route, verified in August 2026, sets the adult passenger at 40 EUR one way and 50 EUR return, and lists two car categories, under 4.25 m and over 4.25 m, both at 100 EUR one way and 150 EUR return. A motorcycle over 250cc is 50 EUR one way and 80 EUR return. The equal fare across both car categories does not mean any vehicle size is accepted, because vessel and vehicle-class limits still apply separately. Turyol, whose conventional ferry Chios also carries vehicles, is quoted at roughly 110 EUR one way and 170 EUR return by a secondary source. Not every sailing carries cars. Only conventional Ro-Ro ferries do; the high-speed catamarans and hydrofoils operated by IDO, Makri Travel, Tilos Travel and Erturk's own fast craft do not, and Erturk's timetable marks the Apostolos S. sailing as No Car. Crossing time is 30 to 50 minutes on the car ferries against roughly 17 to 20 minutes on the passenger-only catamarans. On the Erturk-operated Cesme crossing vehicles must be at the port at least one hour before departure, which is Erturk's own rule and not necessarily that of Turyol, Blue Star or the domestic Greek routes. A traveller online reported seeing a quoted price of 166 EUR for a car plus two adults one way and asked whether buying at the harbour would be cheaper. At Erturk's current published tariff that combination is 180 EUR, being 100 EUR for the car and 2 times 40 EUR for the passengers. The quoted figure sits below today's published fare, so it is either an older or off-peak rate or another operator's pricing. On the Greek side, a Ferryhopper search run on 3 August 2026 for Chios to Piraeus with two adults and one car returned 159.50 EUR in total at 39 EUR per adult, putting the car component at roughly 81.50 EUR for a crossing of 6 hours 45 minutes to 8 hours with Blue Star Ferries. What the rental contract says, and the Ferry Boat Cover. Autohellas Hertz requires the prior written approval of Autohellas Hertz for ferry transport and requires the renter to accept the Ferry Boat Cover at 20 EUR per day capped at 60 EUR per rental; without it the renter is personally liable for damage during the transfer regardless of any other protection paid for. Aegean Rentals, a Crete-based operator quoted as an example of the standard Greek island wording rather than as a Chios firm, states that rented cars may not be taken outside the borders of Greece without the prior written consent, that the car may not be embarked on a ship without the prior written consent, and that if the car is taken off the island, all insurance coverage becomes void. Autounion's terms similarly forbid driving beyond Greek borders. On Chios itself, local firms including J. Vassilakis and Sons, whose office is at the port in Chios town near the Chandris and Kyma hotels, Aegean Atsalis with airport and port delivery, and Hatzelenis Rent a Car publish no ferry or off-island clause on their public pages at all. That silence is not permission: it means the answer is unpublished and must be obtained in writing. CDW and theft protection are standard-excluded while a car sits on a ferry deck unless a specific ferry cover has been purchased, whichever company issued the rental. The vehicle height puzzle: 2.20 m, 2.4 m and 3.5 m. Three different height numbers circulate for these routes and they describe three different things rather than contradicting each other. 2.20 m is the physical clearance of one specific vessel, stated by Sunrise Lines for the Apostolos S., a sailing that is marked No Car on Erturk's timetable in any case. Around 2.4 m is the ceiling of the consumer passenger car booking category on the Piraeus to Chios route, covering the compacted or mezzanine decks where ordinary cars are stowed. 3.5 m, with a 10 m length limit, is Blue Star Ferries' general vehicle allowance, but that clearance belongs to the main freight deck and is reached only by booking the vehicle as a campervan or light commercial vehicle at a higher tariff. Standard passenger cars sit well inside the passenger-car booking category, so most rental sedans and hatchbacks are unaffected; the numbers matter for campervans, roof-box-equipped vehicles and other raised or modified vehicles. Arriving with an undeclared vehicle taller than the category booked means boarding refusal or a forced upgrade charge at the ramp. The practical alternative. Given the notarised-authorisation dead end, the option the constraints leave open is to cross Chios to Cesme as a foot passenger, on either the conventional ferry or one of the faster catamarans run by IDO, Makri Travel or Tilos Travel, and rent a separate car from a Turkish agency on arrival. Cesme is the shortest Turkey to Greece ferry route at roughly ten nautical miles, a 17 to 20 minute hop on the fast boats against 30 to 50 minutes on the car ferries. Erturk Lines also notes that passengers travelling to Chios do not need an international driving licence, which matters for a Turkish visitor planning to rent locally on Chios instead.