Your priorities are to secure the device, protect the phone number and accounts, and restore the connectivity you need for the trip.
Use Apple Find My, Samsung Find or Google Find Hub as appropriate.
Contact your carrier through its official website to report the loss or theft.
Use official recovery pages for email, banking and other critical services. Watch for phishing messages claiming the phone was found.
Once security is handled, decide whether you need a replacement phone, carrier eSIM/SIM or another legitimate connectivity option.
Depending on your situation, you may need a replacement phone, portable charger, tracker, travel connectivity or device protection. Recommended products and services will always be separated from official security actions and clearly disclosed when a link may earn a commission.