An eSIM is a digital SIM card built into your phone. You buy a data plan online, scan a QR code or click a link, and a second mobile number is installed alongside your Australian one. Most iPhones from XR onwards, Pixel 4 onwards and Samsung S20 onwards support eSIM. Check your phone in Settings before assuming.

Can I keep my Australian number while using a local SIM overseas?

Only if your phone supports dual SIM or eSIM. Modern iPhones run two lines at once; one is your Australian eSIM, the other is a local eSIM or physical SIM. Calls and SMS still come through to your Australian number; data routes through the cheaper line.

Will the eSIM work as soon as I land?

Usually yes. Most eSIM providers activate either on first use or at a scheduled time. Install the eSIM at home over wifi before flying; do not wait until you land. Some airports have no public wifi, leaving you stuck without data to install it.

Is roaming ever the right call?

Short trips of under a week to one country, where you mostly need to receive calls and messages on your Australian number rather than browse. A 7-day Telstra Day Pass at $5 to $10 per day costs $35 to $70; an eSIM with 5 GB costs $10 to $15. For trips over a week or with heavy data use, eSIM almost always wins.

Staying in touch overseas: eSIM, roaming or local SIM

Australian mobile carriers charge AUD 5 to 10 per day for international roaming on consumer plans, plus excess data fees. For a 4-week trip that is AUD 140 to 280 of phone bill on top of your normal monthly fee. There are better options for most travellers.

This page covers the three live options in 2026: an eSIM bought online, a traditional roaming pack on your Australian plan, and a local prepaid SIM bought at the destination airport.

Option 1: eSIM (recommended for most trips)

An eSIM is a software SIM downloaded to your phone. You buy it from a provider before flying, install it over wifi, and it switches on when you land.

Major providers operating to popular schoolies destinations in 2026:

Airalo: large global catalogue, country-specific and regional plans, generally cheapest per GB.
Holafly: unlimited-data plans with a flat per-day price, popular but more expensive per GB; useful if you stream or video-call heavily.
Nomad: similar to Airalo, good UK and Europe coverage.
Truphone / 1Global: corporate-focused, sometimes available through your university or workplace.
Maya Mobile, Ubigi, GigSky: smaller alternatives often available in Apple's built-in eSIM marketplace.

Typical 2026 prices for 5 GB of data over 30 days:

Country	Airalo	Holafly (unlimited)	Local SIM at airport
Indonesia (Bali)	AUD 16	AUD 70	AUD 7-12 (Telkomsel)
Thailand (Phuket)	AUD 12	AUD 60	AUD 10-15 (AIS, TrueMove)
Fiji	AUD 25	not always available	AUD 15-25 (Vodafone Fiji, Digicel)
Japan	AUD 14	AUD 65	AUD 25-40 (Sakura, IIJmio)
United Kingdom	AUD 10	AUD 55	AUD 15-25 (giffgaff, Lebara)
United States	AUD 20	AUD 70	AUD 40-60 (T-Mobile, Mint)

Prices move; check a comparison site like esimdb.com or the provider's own page before you buy. The exact data allowance matters more than the brand for short trips.

How to install an eSIM

Check your phone supports eSIM. On iPhone: Settings, General, About; look for "Available SIM" or an EID number. On Android: Settings, Network and Internet, SIMs, or About Phone.
Buy the plan online before flying. Have your departure date ready; some plans start activation on download, others on first use.
Connect to home wifi.
Scan the QR code or follow the email link to install the eSIM.
Label it (Settings, Cellular, the new line). Common labels: "Bali", "Travel", "Data".
Set your Australian SIM to "Primary" for calls and SMS; set the eSIM to "Cellular Data". This keeps your Australian number live while data routes through the cheap line.
Turn on data roaming for the eSIM, off for the Australian line. Otherwise the Australian line tries to roam and bills you.

eSIM gotchas

Activation timing. Some plans activate the moment you install; others when you first connect to a foreign network. Read the fine print so you do not waste two days of a 7-day pass.
Calls. Most eSIMs are data-only. Use WhatsApp or FaceTime to call, or buy a "data plus number" plan if you want a local phone number for booking restaurants.
Hotspot / tethering. Some plans block hotspot or charge extra. Check before relying on it for your laptop.
Phone needs to be carrier-unlocked. New Australian phones sold post-2018 are unlocked by default, but second-hand phones or ones bought from US carriers may not be. Test before you fly.
iPhone 14 and newer in the US. US-market iPhones are eSIM-only and have no physical SIM slot. An Australian-market iPhone has both.

Option 2: Roaming pack from your Australian carrier

Telstra, Optus and Vodafone all sell day-passes or weekly packs.

Telstra International Day Pass:

AUD 5 per day in Zone 1 (NZ), AUD 10 per day in Zone 2 (most popular destinations including UK, USA, Bali, Japan, Thailand).
Includes unlimited calls and SMS to and from Australia, plus a daily data allowance (typically 1 GB in 2026).
Only charges on days you use it.

Optus International Roaming:

AUD 10 per day in 60+ countries.
Unlimited calls and SMS, 5 GB daily data.
Auto-applies, opt out by texting CANCEL to 9999.

Vodafone $5 Roaming:

AUD 5 per day in 80+ countries.
Uses your home plan's calls, SMS and data abroad.

Roaming makes sense if:

The trip is short (under 7 days) and your phone is your main communication tool.
You need your Australian number live for work, banking SMS codes, or family.
You travel to multiple countries in one trip; an eSIM is per-country and switching plans gets fiddly.

Roaming makes less sense if:

You will use a lot of data (maps, streaming, video calls).
You are gone for over two weeks.
You are happy with a separate local number.

Some banks send 2FA codes only to your registered Australian number. Roaming or dual-SIM eSIM lets the SMS through; a pure local SIM does not. Check your bank's two-factor setup before leaving.

Option 3: Local prepaid SIM

Walking up to an airport kiosk and buying a local SIM is the oldest method and still works.

Pros:

Often the cheapest data per GB once you are in the country.
You get a local number, useful for booking restaurants or transport apps that need SMS verification.
No need for an unlocked or eSIM-capable phone.

Cons:

Replaces your Australian SIM unless your phone is dual-SIM. Your Australian number then goes to voicemail.
Airport kiosks charge a markup vs in-town providers (Telkomsel in Bali sells for half the price in Denpasar versus the airport stand).
Identity verification can take time. Indonesia, Thailand and many other countries require passport registration; some kiosks set up the SIM for you in 10 minutes, others take longer.
You need to know which provider has coverage where you are going. In Fiji, Digicel covers more of Vanua Levu than Vodafone Fiji.

Practical tip: at major tourist airports (Denpasar, Phuket, Suva, Tokyo Narita, London Heathrow, Los Angeles), local SIM kiosks are visible on the way out of arrivals. Take cash in the local currency for the first sim purchase if you can; some only accept cash.

How to choose

For a 1-2 week trip to one country with moderate data use:

Bali, Phuket, Tokyo, London: eSIM almost always wins. Install Airalo or similar before flying.
Fiji, Vanuatu, smaller Pacific islands: local SIM at the airport is often cheaper and more reliable than eSIM coverage outside the main resort areas.
Multi-country trip (Europe rail, Asia loop): regional eSIM (Airalo Asialink, Eurolink) avoids switching SIMs in every country.

For trips over 4 weeks:

A local prepaid SIM is usually cheapest. Buy a 30-day pack and top up as needed.
Or stack a long-duration eSIM (60 or 90 days) and avoid hassles at the airport.

Wifi calling

If your home plan supports wifi calling (Telstra, Optus, Vodafone all do), you can receive and make calls on your Australian number over any wifi connection, with no roaming charge. This is the cheap fallback when you do not need data on the go: rely on hotel and cafe wifi.

The catch is that some networks block voice-over-wifi internationally. Test by enabling wifi calling at home, then putting your phone in airplane mode with wifi on; if it makes calls, it should work overseas.

What to do before you fly

Pick your option (eSIM, roaming, local SIM) based on the trip length and destination.
If eSIM: buy, install and test it on home wifi.
Disable data roaming on your Australian SIM if you are not using a roaming pack. This prevents the dreaded "I forgot and got charged $400" outcome.
Save offline copies of maps (Google Maps offline area, Maps.me) before flying.
Save 24-hour emergency numbers offline: family back home, embassy or consulate, insurance assistance line, accommodation.

ExamExplained is not affiliated with any eSIM or telecommunications provider; provider names appear because they are widely used. Prices in this guide are typical 2026 retail and move quickly. Check the provider's live page before buying.