GUIDES
Original guides for travel across borders: each one solves a specific problem and states its dates and sources.
CROSS-BORDER GUIDES
Articles are updated as needed; information about prices, policies and standards states its review date.
Maps, messaging and mobile payments in urban Hong Kong barely work without data. Narrow the choice by trip length, phone compatibility and whether your usual number must stay reachable — then install an eSIM at home, enable roaming, or buy a prepaid SIM after landing.
Trip length is only the starting point. Video quality, autoplay, cloud backup and tethering usually decide how many gigabytes you should buy — more than the number of days.
Do not wait until arrival to discover an incompatible phone, an expired QR code or the wrong data line. Installing and activating are two steps: install while you have internet, turn data on after you land.
Limits vary by airline, cabin and fare. First check whether the included piece is an under-seat bag or an overhead cabin case, then measure the packed bag with wheels and handles.
The plug decides whether it fits. The voltage decides whether the device survives. Wattage decides whether a transformer is large enough. Order: read the label, check the socket, then consider a transformer only for single-voltage, high-power gear.
Offline maps use GPS, not mobile data. Pick the app and the region before you leave, then learn which features still need a network after you land.
Read the airline’s size and weight first, then pack for the number of days. A bag that fits the sizer empty may not when it is full.
Compare the medical limit, cancellation reasons and baggage cap first. Price is easy to rank; exclusions decide whether a claim pays. This page is not a sales pitch or advice to buy.
Checked baggage allowances are set per route, cabin and fare. First see whether this ticket uses weight, pieces, or a low-cost paid add-on, then measure and weigh the packed bag.
Most checkpoint queues come from three things: oversize liquid bottles, a laptop buried in the bag, and a power bank in checked luggage. Departure and transfer airports can disagree; pack to the stricter stop.
Most problems abroad start as unfinished chores at home. Work through seven days out, two days out and the departure day, then leave.
Spending abroad usually has two costs: your issuer’s foreign transaction fee, and the spread charged by a terminal or exchange desk. Separate them before you choose which card to pack and how much cash to carry.
A budget is nights times lodging plus calendar days times daily spend, then flights and a buffer. Count the days first, then use destination prices — not habits from home.
Jet lag is the body clock still running on the departure city while the destination is already on another day-night cycle. It is most obvious after three or more zones. Direction, light and the first two days matter more than sleeping the entire flight. This page is not treatment.
Maps, translation and messaging in Tokyo, Osaka and Kyoto barely work without data. The best option depends on how many devices you carry, how long you stay and whether you need calls — lock that in first, then install an eSIM at home, rent pocket Wi-Fi at the airport, or buy a prepaid SIM after landing.
When people are 8–15 hours apart, the realistic overlap is often only 2–4 hours a day. Find the window, then pick a fair point inside it, then write the invite. Do not subtract a memorised offset in your head.
A short layover is not automatically visa-free. Your passport, airport route, ticket structure and baggage process can each change the answer.
A familiar home-currency amount on a terminal is not a discount. Decline merchant conversion first, then calculate the fees in your own card agreement.
A phone that supports Personal Hotspot does not prove that a travel eSIM plan permits tethering. Separate plan, data-line and connected-device checks before relying on it abroad.
Hotel “3 nights” and a tour’s “3 days 2 nights” are not the same unit. Split nights from calendar days before you match a leave form or the morning you fly home.
Most trips need data for maps, translation and ride-hailing. Decide from stay length, how many devices you carry and whether you need a Thai number — then install an eSIM at home or take a passport to a counter.
Seoul and Busan trips need data for maps, translation and ride-hailing. Decide from stay length, how many devices you carry and whether you need a Korean number — then install an eSIM at home or take a passport to an Incheon or Gimpo roaming counter.
Paris to Rome to Barcelona is a network-switch problem, not a reason to buy three SIMs. First ask whether you already have EU roam-like-at-home on a home plan, then check whether the regional eSIM list includes the UK and Switzerland.
New York, Los Angeles or a national-park loop all need data for maps and ride-hailing. This page is for inbound visitors and short stays. It does not assume which country you flew from. Start from trip length, whether you need a US number, and whether you can install a profile before take-off.
In mainland China the real question is not “will I have data” but “will my usual apps work”. Google, WhatsApp, Instagram and similar services are not directly accessible on mainland networks — and whether you need them decides between roaming, a travel eSIM that routes outside the mainland, or a registered local SIM.