Freeing up phone storage before a trip

First, see what is actually filling the phone

On iPhone, Apple's path is Settings, General, iPhone Storage. The free space appears at the top, with Apple's recommendations and a list of apps and how much each one uses; tap Show All to see them and Enable to apply one. On Android, Google's path is Settings, Storage, where you can open each category to see what is using space. Google notes that some of these storage steps only work on Android 14 and later.

Look at the list before deleting anything. On a phone that is nearly full, the usual culprits are photos and videos, message attachments, offline downloads from streaming apps and a few large apps you rarely open. Apple names exactly those as the common sources of storage use. Knowing which one is yours saves you from deleting things you will miss and keeping the thing that matters.

iPhone: the tools Apple gives you

• Offload Unused Apps: Settings, Apps, App Store. When storage is low, the iPhone removes apps you do not use but keeps their data; the icon stays with a cloud symbol and one tap reinstalls it.
• One app at a time: in iPhone Storage, tap an app and choose to offload it, which keeps its documents and data, or delete it, which removes them too.
• Downloaded videos: Apple suggests reviewing what you saved for offline viewing in the TV app and other streaming apps and removing what you have watched.
• Messages: delete conversations and attachments you no longer need.

For photos, Apple's option is Optimize iPhone Storage in iCloud Photos, under Settings, your name, iCloud, Photos: full-resolution originals stay in iCloud and the iPhone keeps space-saving versions. It needs enough iCloud storage, and Apple says every account starts with 5 GB free. Photos you delete go to Recently Deleted for 30 days before they are removed for good, so empty it if you need the space now.

Android: Settings, Files by Google and archiving

• Free up space: in Settings, Storage, tap Free up space, choose a category, tap Select files and then Move files to Trash.
• Files by Google: tap Menu, then Clean; on the Junk files card tap Clean and confirm with Clear. Google warns that what you delete with Files by Google is deleted permanently.
• Archive apps: Settings, Apps, choose the app and tap Archive. Google says this removes the app's software, permissions and temporary files but keeps the icon and your data; a tap on the faded icon reinstalls it. Some archiving steps need Android 15 or later.
• Google Photos: tap your profile picture, then Free up space on this device, and Free up to remove the backed-up copies from the phone.

Clear cache in an app's storage settings deletes temporary data, while Clear storage deletes all of the app's data permanently. Google advises trying to delete data inside the app first. Menu names can vary by phone maker.

The catch: what leaves the phone needs data to come back

Every cloud trick above trades storage for a connection. Google says that after you free up space in Google Photos, you cannot see the removed photos in your phone's gallery, while offline or when not signed in. Apple's optimized photos are smaller copies, and the originals download over Wi-Fi or mobile data when you open them. An offloaded or archived app has to be downloaded again before you can use it. At home that is nothing; on a train with no signal, or on your first day with only roaming, it is a problem.

So decide what must stay on the phone. Boarding passes, tickets and booking confirmations should be saved locally, as explained in keeping travel documents offline. Do not offload the airline, train or transport apps you will need on arrival. And keep a few recent photos of documents or your parking spot in the gallery rather than only in the cloud.

Back up first, then make room for the trip

Never free space by deleting photos that are not backed up. Google Photos itself advises checking the backup before using Free up space, and notes that photos and videos less than 30 days old may stay on the device. If you have not run a full backup recently, do that first; backing up your phone before a trip covers iCloud, Google, WhatsApp and authenticator codes.

Once there is room, fill it on purpose: offline maps of the places you are visiting, as in using Google Maps offline, films and music for the flight from downloading before a flight, and translation packs. All of this is better downloaded at home than over mobile data. Leave some space free as well, since the photos and videos you take on the trip need somewhere to go.

During the trip: storage and mobile data go together

Whatever you moved to the cloud will try to come back over mobile data when you open it, and new photos will try to upload. If you want backups to wait for Wi-Fi, stopping photo backup on mobile data shows the settings for iCloud and Google Photos. If you prefer to keep backing up as you go, count it in your data: the data calculator helps size a plan for that. A Snoozim data eSIM can be topped up without reinstalling if the photos take more than you planned.