I've overpacked, underpacked, and had gear damaged or nearly confiscated on international trips over the years, and here's the actual, deliberate system I've built after enough individual mistakes to finally arrive at a process I trust rather than reinventing my packing approach before every single trip.
Camera and lenses always travel as carry-on, never checked, a rule I don't break regardless of how much easier checking a bag would occasionally be. Checked baggage handling is rough enough, and delayed or lost baggage common enough, that the risk to genuinely expensive, hard-to-replace equipment simply isn't worth the convenience.
I've settled on a single, well-padded backpack-style camera bag rather than a rolling case, since a backpack keeps both hands free navigating unfamiliar airports, train stations, and crowded streets, a genuinely practical consideration that matters more once you're actually moving through an unfamiliar city than it does packing at home.
Lens selection for travel is deliberately more limited than my full working kit. I bring one versatile zoom covering my most commonly needed range, one fast prime for low light and portrait work, and rarely more than that, resisting the urge to bring every lens I own "just in case," a habit that cost me real shoulder pain on early trips before I disciplined myself to travel lighter.
Batteries and chargers get genuine deliberate attention before international trips specifically. I research the destination's power standards in advance, bring a single reliable universal adapter rather than multiple cheaper ones, and always pack at least one more spare battery than I think I'll realistically need, since finding a compatible replacement battery abroad, especially for less common camera systems, can range from difficult to genuinely impossible.
Memory cards get split across multiple smaller-capacity cards rather than one or two large ones, a deliberate choice so that losing or corrupting a single card never risks an entire trip's worth of images, only a fraction of it.
I photograph my gear's serial numbers and keep that documentation, along with proof of prior ownership, in cloud storage before departing, specifically in case of a customs question about whether equipment was purchased abroad, a genuine issue I encountered once returning from an international trip that cost real time and stress to resolve without documentation readily available.
A basic cleaning kit, a rocket blower, a microfiber cloth, and a small bottle of lens cleaning solution, travels in every bag regardless of trip length, since dust and environmental grime accumulate faster during heavy travel use than during normal daily shooting at home.
I carry a portable SSD for backing up images each evening, separate from my laptop, specifically so a single lost or stolen bag can't take out both my primary camera cards and my only backup simultaneously, a habit built directly from a genuine scare on an earlier trip where a bag was briefly misplaced.
Insurance specifically covering travel and international use, confirmed before departure rather than assumed from a general homeowner's or renter's policy that may not actually cover equipment abroad, has become a standing pre-trip checklist item after learning the hard way that not every policy automatically extends coverage outside your home country.
For airport security specifically, I keep camera gear easily accessible near the top of my bag rather than buried beneath clothing, since security screening in many countries requires removing electronics for separate scanning, and a bag that's quick to open and repack saves genuine time and frustration moving through checkpoints.
Weather and climate research for the specific destination shapes what protective gear I bring beyond the camera itself, a rain cover for a tropical destination, extra battery capacity and a way to keep batteries warm for cold climates where battery performance genuinely suffers.
None of this is complicated individually, but building it into a consistent, repeatable pre-trip checklist rather than relying on memory or improvising fresh before every trip is what's actually eliminated the recurring mistakes I used to make traveling with gear internationally.
A specific trip where nearly everything that could go slightly wrong did, a delayed connection, an unexpected downpour, a hotel with unreliable power, became the real stress test for this whole system rather than any single planned scenario. Having spare batteries already charged, a rain cover packed without needing to think about it, and a backup drive with the previous days' images already secured meant none of those individual problems became a genuine crisis, which is really the entire point of building redundancy into a travel kit before you actually need it.
Language and customs research specific to photography also deserves a place on this checklist, since some countries and specific sites have restrictions on professional-looking equipment, tripods in particular, that casual tourists with phones never encounter. Researching this in advance for a specific destination has saved me from arriving somewhere only to discover gear I'd planned to use for a shoot wasn't permitted without a permit I hadn't known to arrange beforehand.