1GB, 3GB, 5GB, 10GB or 20GB eSIM: How to Choose and How Much Data Your Trip Needs

Five things to remember

Estimate daily use first, multiply by trip length, then add 20% headroom. Most travellers use 0.7–1.2GB a day; maps and messages alone are about 0.3–0.5GB; video, hotspotting and photo uploads push past 2GB.
For 1–3 days choose 1GB or 3GB; 4–7 days, 3GB, 5GB or 10GB; 8–14 days start at 10GB; 15–30 days start at 20GB.
5GB is the sweet spot for a typical week: about 0.7GB a day with room to spare. 20GB suits longer trips, hotspot use and uploads; it does not mean unlimited speed.
Video decides everything. Netflix publishes up to 0.3GB an hour on low, 0.7GB on medium, 1GB SD, 3GB HD and 7GB on 4K. One hour of HD can eat a large part of a 1GB plan.
Check validity, not only gigabytes. Most plans start when the eSIM first connects to a local network, not at payment. A 30-day 20GB plan is cheap per GB, but a short trip wastes the remaining days.

Traveller checking a map and eSIM data on a phone at the airport — The photo shows a travel and phone scene, not any operator’s plan. Prices and validity are those shown at checkout.

How much data a day actually takes: start with a baseline

A data tier is not a speed tier. A 1GB and a 20GB plan use the same local network; the difference is how much you can transfer and how long the plan stays valid. So the first question is not price. Convert your usual day into gigabytes. Maps and messages are light, video and hotspotting are heavy, and the gap between them is two orders of magnitude.

Activity	Approximate use per hour	Note
Maps and navigation	5–15MB	Lower with offline maps
Messaging and email	3–10MB	Text is tiny; photos and voice notes add up
Web and travel guides	50–100MB	Image-heavy pages sit at the top
Social feeds	100–300MB	Autoplay video pushes it higher
Short video (TikTok, Reels)	0.7–0.9GB	Heavier than standard long-form video
Music	40–150MB	Spotify: about 43MB at 96kbps, 144MB at 320kbps
Video calls	0.3–0.9GB	HD group calls at the top end
Standard video	0.5–1GB	Netflix: about 0.3GB low, 0.7GB medium
HD video	1.5–3GB	One hour can exceed a normal daily budget
4K video	Up to about 7GB	Netflix’s stated ceiling; unnecessary on a phone
Laptop hotspot	0.5–1GB a day	Email and web only; video is extra
Cloud photo backup	0.5–2GB a day	Set it to Wi-Fi only

Netflix’s help centre is precise: low uses up to 0.3GB an hour, medium up to 0.7GB, and high quality up to 1GB in SD, 3GB in HD and 7GB in 4K. Spotify’s official audio-quality table lists 96kbps and 320kbps, which work out to roughly 43MB and 144MB an hour. Maps usually cost a few megabytes an hour. Video, hotspotting and background backup are what empty a plan. Sources: Netflix data usage, Spotify audio quality.

The most accurate baseline is your own phone. On iPhone, open Settings → Cellular and check each app for the current period. On Android, open Settings → Network & internet → Data usage. Take the last 30 days’ daily average, multiply by trip length, then add 20% for maps, updates and the occasional hotspot. That number is closer to you than any “average traveller”.

Pick a tier by trip length: a table you can buy from

Put daily use and trip length together and the five tiers fall into place. “Light” means maps, messages and a few photos; “typical” adds social media and music; “heavy” means video, hotspotting or uploading footage.

Trip length	Light use	Typical use	Heavy use
1–2 days	1GB	1–3GB	5GB
3–4 days	3GB	3–5GB	5–10GB
5–7 days	3–5GB	5–10GB	10–20GB
8–14 days	5–10GB	10–20GB	20GB or more
15–30 days	10–20GB	20–50GB	Unlimited or 50GB+

Read validity before gigabytes. Many 1GB plans last only 3–7 days; 3GB and 5GB often run 7–15 days; 10GB and 20GB usually 15–30 days. Buying 20GB/30 days for a four-day trip lowers the unit price, but you cannot take the rest home. Buying 5GB/7 days for a 20-day trip means buying again in week two.

For long trips, “base plan plus top-up” is steadier: start with 10GB or 20GB, then top up the same eSIM when it runs low. Top-ups can cost more per GB than the first purchase and may have minimum tiers, so check the top-up price before departure. If auto-renewal is offered, confirm whether it charges at 10% remaining or only at expiry.

Who 1GB, 3GB, 5GB, 10GB and 20GB each suit

1GB: layovers, weekends and Wi-Fi-first trips

For 1–3 days of maps and messages. 1GB covers plenty of navigation, chat and a few photos, but not video: one hour of HD can use 1–3GB. Buy it when the hotel, airport and cafés have reliable Wi-Fi and the eSIM only has to cover the journey to your accommodation.

3GB: a light-to-moderate 3–5 day trip

At 0.5–0.8GB a day, 3GB covers 3–5 days of maps, social media, music and the occasional short video. What it adds over 1GB is not luxury but tolerance: one hotspot session, one video upload or a rerouted map will not leave you empty by evening.

5GB: the default answer for most 5–7 day trips

Over seven days, 5GB is about 0.7GB a day, right in the typical band. Maps, messages, a few social posts, some music and short calls all fit. If you watch 30 minutes of HD video every day, 5GB gets tight; go straight to 10GB.

10GB: 7–14 days typical, or 5–7 days heavy

10GB is the “stop counting every day” tier. It covers two weeks at about 0.7GB a day, or one week at about 1.4GB a day. It suits 30–60 minutes of HD video a day and the occasional hotspot for email. If you have more than an hour of video meetings daily, even 10GB may not be enough.

20GB: long trips, remote work and uploads

20GB suits 14–30 days, or seven days of heavy use. Hotspotting a laptop, uploading camera footage and long video calls all push use above 2GB a day. It is not unlimited: many 20GB plans are hard caps that stop or throttle when empty. True “unlimited” plans usually have a daily high-speed limit; in Japan, for example, a common rule is 3GB at high speed per day, then 1Mbps. Check the operator’s terms.

So the five tiers are not “the more expensive, the safer”. They are “the closer the fit, the less you waste”. A big plan on a short trip saves per GB but wastes validity; a small plan on a long trip costs a second purchase and a risk of going offline. Fix the days, then the usage, then the price.

Light, typical and heavy: multiply the daily figure

The arithmetic below uses three planning baselines: light 0.3–0.5GB a day, typical 0.7–1.2GB, heavy 2–4GB. These are estimates, not an account export. Replace them with your own phone history if you have it.

Type	Per day	7 days	14 days	Typical behaviour
Light	0.3–0.5GB	3GB	5–7GB	Maps, messages, a few photos; video at the hotel
Typical	0.7–1.2GB	5–10GB	10–20GB	Social, music, short calls, some short video
Heavy	2–4GB	15–20GB+	30–50GB or unlimited	Daily video, hotspot, footage uploads
Remote work	2–5GB+	20GB+	50GB+ or unlimited	Video meetings, cloud drives, laptop hotspot

Light users are the easiest to upsell into 20GB, but if a week only uses 2–3GB the extra allowance is not refunded. Typical users are the core of the 5GB and 10GB tiers: 5GB for a week, 10GB for two weeks, with a little headroom. Heavy users should not trust an average; plan for 3GB a day, or buy an unlimited plan with a published daily high-speed allowance.

Remote work deserves its own line. An hour of HD video meetings is roughly 0.5–0.9GB, so four hours is 2–3.6GB before cloud sync and code pulls. The cheapest setup is hotel Wi-Fi for meetings and large files, with the eSIM as backup and for email on the move. If everything must run on cellular, 20GB lasts only a few days; look at unlimited or 50GB.

The hotspot is another hidden switch. A laptop doing email and documents often uses 0.5–1GB a day. Once you stream video or sync large files through it, usage stacks on top of the phone’s own. Setting OS updates, cloud photos and podcast downloads to Wi-Fi only often saves more than 1GB.

Price, price per GB and validity: when bigger is not better

A snapshot of Japanese market prices on 10 October 2026 put 1GB at about $3.49–4, 3GB at $6.99–8, 5GB at $9.99–11, 10GB at $14–18 and 20GB at $22.99–25. Seven-day unlimited was about $25–27.50. Providers and validity differ widely; the checkout page is the final price. Snapshot: Travelsim Asia comparison.

Per GB, 1GB is about $4/GB and 20GB about $1.25/GB, so bigger looks cheaper. But a lower unit price does not make the purchase good value. If a four-day trip uses 4GB, a 20GB plan spends about $14 on data you will never use and carries the risk of expiry. The right comparison is the smallest tier above actual trip need plus 20%.

Separate three product shapes: fixed data (stops or throttles when empty), unlimited with a fair-use policy (throttled after a daily high-speed allowance), and daily plans (allowance resets each day). Fixed data suits predictable use; unlimited suits heavy video and hotspot use, but read the daily cap; daily plans suit a fixed trip with even usage. Check “what happens after the cap” and “can I top up” before buying.

Eight checks before buying

Choosing the right tier is only half the job. If any of these fails, even 20GB may not help.

The phone supports eSIM and is carrier-unlocked. On iPhone, Settings → General → About shows Carrier Lock; “No SIM Restrictions” means a travel eSIM can be used.
Destination coverage. Local, regional and global plans differ; if you transit through a third country, confirm it is included.
Validity and activation. Most plans start on first connection to the local network, not at payment. Install early, activate on arrival.
Hotspot allowed. Some cheap data plans forbid tethering, so 20GB will not drive a laptop.
Number and SMS included? Data-only eSIMs usually cannot receive bank verification codes; keep important accounts on your home line.
Top-up rules. Confirm whether the same eSIM can be renewed, whether top-ups cost more, and whether unused data carries over.
Can it be restored after deletion? Many providers do not guarantee a free reissue after an eSIM is removed. Keep the QR code and activation details.
Fair-use policy and refunds. Where the high-speed cap sits, how slow “throttled” is, and whether an unactivated plan is refundable all change the real experience.

Apple’s guidance adds one practical point: a travel eSIM can run as a secondary line alongside your home number. Data goes through the travel eSIM, while the home line can still receive calls and texts, potentially with roaming charges. Before departure, choose the default data line under Settings → Cellular and turn off data roaming on the home line. Sources: Apple travel eSIM guide, Apple eSIM setup.

FAQ

How many days does 1GB last?

With maps, messages and a few photos, 1GB lasts about 2–3 days. With daily video or hotspot use it can disappear in half a day. It suits layovers, short weekends or trips with reliable hotel Wi-Fi.

Is 5GB enough for a week?

For most people, yes. Five gigabytes over seven days is about 0.7GB a day, enough for maps, messages, social media and some music. If you watch HD video daily, hotspot or upload footage, choose 10GB or 20GB.

10GB or 20GB?

For 7–14 days of typical use, 10GB is usually enough. For more than 14 days, daily hotspotting, uploads or long video calls, choose 20GB. The price gap may be only a few dollars, but check validity first: a 20GB/30-day plan on a short trip leaves data behind.

Does “unlimited” mean I can use anything?

No. Most unlimited plans have a fair-use policy, such as throttling to 1Mbps after the daily high-speed allowance. Before streaming or hotspotting, read the daily cap and the post-throttle speed in the operator’s terms.

What if I run out of data?

First check whether the same eSIM can be topped up; if it can, do not delete it. If not, or if no suitable top-up exists, buy another data eSIM. Save the provider’s top-up page and support contact in an offline note before you fly.

When does the trip clock start?

Most plans start on first connection to the destination network and count in local 24-hour periods or calendar days. Buying and installing do not activate the plan, so you can install at home and switch the line on after landing.

The one-line answer

Set the tier from 0.3–0.5GB a day for light use, 0.7–1.2GB for typical use and 2GB+ for heavy use; multiply by days, add 20%, then correct with validity and top-up rules. When unsure, buy one tier smaller and top up. The real saving is not the lowest price per GB, but a plan that is just enough for the whole trip.