The short answer
If a rented vehicle is missing abroad, first move to a safe staffed place and establish that it was not towed, relocated or collected by the rental company. Do not follow a tracker or attempt recovery. Use the exact local police route, then notify the rental company through the contract channel and follow its instructions for keys, documents and any replacement. Preserve only proportionate evidence and keep insurer administration separate. A data-only eSIM may support later non-critical web tasks on a compatible unlocked phone; it cannot call police, locate or recover the vehicle, authorise a replacement, decide liability or guarantee reception.
Get safe and establish what is actually missing
Move away from any confrontation or unsafe location and use the local emergency route if there is immediate danger, injury or coercion. From a safe staffed place, record where and when you last saw the vehicle, its registration, make, model, colour, rental company and contract reference without posting those details publicly. Check only through authorised parking, towing, accommodation or rental channels whether the vehicle was moved or collected. Do not approach a suspected person, enter private property or follow a live tracker. A map pin is information for the competent authority, not permission to recover the car yourself.
Use the exact local police reporting route
The correct emergency threshold, police office, online-report option, interpreter route and required documents vary by country. Ask the competent local authority whether to call, attend in person or use an official portal, and whether you may leave the location. Give facts rather than assumptions and obtain the authority name, report reference and correction process when available. The European e-Justice Portal links country-specific victim information across the EU; it does not create one worldwide procedure. An online submission or automated receipt is not proof that a report has been formally accepted.
Let the rental company control its vehicle and contract
Contact the branch or assistance channel printed in the verified rental agreement, not a number from an unsolicited search result or message. Report the police reference when permitted and ask exactly what to do with every key, the contract, registration papers, parking ticket and any company device still in your possession. Ask whether driving another vehicle, arranging transport, ending the rental or collecting a replacement is authorised, where it happens and what payment or deposit is required. Do not rent a substitute at your own initiative on the assumption that it will be reimbursed. The rental company, police and insurer have different roles.
Preserve proportionate evidence and separate insurance
Write a factual timeline and securely retain the signed agreement, checkout condition record, key handover, police reference, rental-company instructions and necessary receipts. Do not publish the registration, contract, identity papers, card details, accommodation address or tracking access. Read the rental protection and any separate travel, card or motor policy for notice deadlines, exclusions, excess and approved channels before sending files. A police report does not determine contract liability; a rental-company charge does not by itself prove insurer coverage; an insurer acknowledgement is not claim acceptance. Ask each responsible party for its decision in writing.
Continue only from transport that was actually accepted
Rebuild the itinerary from the outcome confirmed by the rental company and relevant authorities. Include the safe way away from the reporting location, any branch visit, replacement collection, changed accommodation, border crossing and return appointment. Confirm who pays and whether a new driver, deposit, licence check, ferry or cross-border permission is required; the original contract may not transfer. Save non-sensitive directions, booking confirmations and meeting points offline, and keep an independent urgent-contact route. If personal belongings were inside the vehicle, list them privately and use the separate item-specific phone, card, passport or theft processes rather than assuming the vehicle report completes them.
Compare only the ordinary data that remains
After safety, police reporting, rental instructions, required calls, evidence and accepted onward transport are secured, list only non-critical internet tasks such as opening a verified portal, ordinary messaging, checking a confirmed route or uploading a permitted document. Subtract tested Wi-Fi, working home roaming and offline files. Continue only when every country of use is listed, validity and activation fit the changed trip, and the available phone is unlocked and compatible. Stop if you require emergency or police calling, carrier SMS, a local number, continuous tracking, vehicle recovery, replacement approval, insurer acceptance or guaranteed road reception; current CheapESIM offers provide none of those outcomes.