How to Call Overseas from Different Networks

Overseas Calling Options by Network

When you need to call overseas, your network choice matters. Carriers offer several paths: direct international dialing using your mobile plan, prepaid international add-ons, call forwarding and roaming, and third-party Voice over IP (VoIP) apps that use WiFi or mobile data. Below are the typical options for common networks and the practical trade-offs.

• Mobile operator international dial (IDD)
  • Use your carrier’s international service and pay per-minute or via a bundle. This works without any extra apps, but rates vary by destination.
• Roaming and Wi‑Fi calling
  • If you keep your home SIM active while abroad, enable roaming or Wi‑Fi calling to make and receive calls. Roaming avoids changing numbers but can cost more unless you buy a roaming pack.
• Local SIM or eSIM
  • Buy a local prepaid SIM or eSIM for cheaper local and regional calling/data, especially for long stays.
• VoIP apps over Wi‑Fi/data
  • Apps that call real phone numbers let you use Wi‑Fi or mobile data instead of depleting roaming minutes. These can be the cheapest option for many destinations. See our explainer on VoIP phone services and how to make international calls.
• Callback/calling cards and virtual numbers
  • Callback services or virtual phone numbers can cut costs for specific routes. Learn about virtual numbers in our virtual phone numbers guide and free virtual phone numbers.

Network-specific notes:

• EE (UK): You can call international numbers directly using + or 00. If you’re an EE customer abroad, enable roaming or Wi‑Fi calling to use your EE number. For guidance on both directions, see the step-by-step dialing section below.
• Globe (Philippines): Dial with + or 00 then the country code and number. Globe also offers add-ons for discounted international calls.
• Singtel / StarHub (Singapore): Singapore uses international access prefixes tied to carriers. Singtel’s IDD prefix is 001, StarHub commonly uses 002, and M1 uses 008. You can also dial +country code directly on most phones.
• Smartone (Hong Kong) and Cellcard (Cambodia): Both follow standard international dialing using + or 00; they support standard GSM call forwarding codes for diverting calls overseas.

If you plan to call often, compare your carrier’s published rates with VoIP alternatives. For example, Telvio offers per‑second billing, no connection fees, and rates from $0.02/min to the US and $0.08/min to India, and you can call real phone numbers over Wi‑Fi or mobile data without using cellular minutes.

Step-by-Step International Dialing Instructions

International dialing follows a simple pattern: exit code (or +), country code, then the national number (dropping any leading zero). Here’s how to do it from different starting points.

1. Use the + symbol (recommended)
   • Open the dialer, press and hold 0 until + appears. Dial +, then the country code, then the national number (omit any leading zero).
   • Example: Calling a UK EE mobile from Singapore: dial +44 7xxxx xxxxx (drop the 0).
2. Use the local international access code
   • Many countries use 00 as the access code (Europe, much of Asia). Some carriers in Singapore use 001/002/008 to route international calls.
   • Example: On Singtel: dial 001 then 1 415 555 0123 to call a US number. On StarHub: dial 002 then the country code and number.
3. Calling from a phone while roaming (calling out on your home number)
   • Turn off airplane mode, ensure data/voice roaming is enabled if required, and dial as you would at home using +country code. Some phones allow you to simply dial the home number, but using + avoids confusion.
4. Calling a number in the country you’re visiting (local calls)
   • Dial the local number directly without international prefixes. If the number used to require a leading zero, keep it only if it’s national dialing format.
5. Calling toll-free or 1800 numbers
   • Many 1800 numbers (e.g., US 800, AU 1800) do not accept international calls when dialed directly. Try the company’s international/toll or local contact number, use a local access number, or place the call through a VoIP app that supports toll-free access. See “Call 1800 from overseas” in the FAQ for examples.

Quick practical examples:

• From the United States to the Philippines (using +): +63 912 345 6789
• From Singapore to India using Singtel IDD: 001 91 22 1234 5678
• From the Philippines (Globe) to the US: +1 415 555 0123 or 00 1 415 555 0123

If you want a walkthrough of calling with Wi‑Fi apps, check our guide to free online video calling platforms and how VoIP compares to carrier calling.

Cheapest Ways to Call Abroad

Cost often decides the method. Here are practical, cost-focused choices with examples.

1. VoIP apps over Wi‑Fi or mobile data
   • Use a VoIP app that dials real phone numbers. You pay per minute or buy credit packs that last. Telvio, for example, bills per second with no connection fees, offers credit packs ($1.99 Starter, $4.99 Standard, $9.99 Pro), credits never expire, and gives 1 free minute on first install. Telvio’s rate example: $0.02/min to the US, $0.08/min to India. For many users calling from Singapore to the Philippines or the UK, VoIP apps will beat carrier IDD rates.
2. Local SIM / eSIM
   • Buy a local prepaid plan for low local rates. This saves more on long stays and local calls. Use an eSIM for convenience on compatible phones.
3. International calling packs from your operator
   • Carriers sell bundles that cut per‑minute costs for specific zones. For short trips, these can be cheaper than roaming by the minute—compare the math before buying.
4. Callback and calling cards
   • Callback services can reduce costs on some routes, but they add steps and sometimes hidden fees. Use only reputable providers and check final per-minute charges.
5. Free or low-cost alternatives for some contacts
   • If the person you’re calling also has a smartphone, use free apps (voice or video). See free options in our free online video calling platforms guide.
6. Virtual local numbers
   • Rent a virtual local number in the destination country and forward calls to your phone or VoIP app. This can be useful for receiving calls without roaming. Learn more in our virtual phone numbers guide.

Cheap example: If a carrier charges SGD 0.50/min to the Philippines, but a VoIP service charges USD 0.03/min, even with data cost factored in, VoIP will usually save money — especially for long calls.

Tips to keep costs down:

• Prefer Wi‑Fi for VoIP calls.
• Use per‑second billing options instead of per‑minute where possible.
• Avoid in-call connection fees.
• Compare total costs, including service fees and taxes.

Avoiding Roaming Charges

Roaming charges can add up quickly. Use these tactics to avoid or reduce them.

• Turn off data roaming and use Wi‑Fi
  • Put your phone in airplane mode and enable Wi‑Fi. Use VoIP apps to call and receive calls over Wi‑Fi rather than using roaming voice or data.
• Use Wi‑Fi calling where supported
  • Many carriers and phones support Wi‑Fi calling with your home number. Enable it before you leave and test it on Wi‑Fi.
• Buy a local SIM or eSIM for extended stays
  • Switching to a local plan avoids roaming fees for data and local calls.
• Use call forwarding to a VoIP number
  • Forward your home number to a VoIP or local number to receive calls without roaming. Be aware forwarding may incur charges from your home carrier; use conditional or time-limited forwarding as needed.
• Get an international roaming pack if you need to keep your home number
  • For short trips or when you must receive calls on your home number, a short-term roaming bundle can cap costs.
• Use Wi‑Fi-based business tools
  • Use online meeting tools and virtual phone solutions to handle business calls without roaming. Read our VoIP phone services explained for options.

Practical setup for the cautious traveler:

• Before you leave, enable Wi‑Fi calling and download your VoIP app of choice.
• Turn off roaming data to avoid accidental charges.
• If you expect incoming calls to your home number, consider forwarding them to your VoIP number or setting an auto‑reply with alternative contact details.

Network-Specific International Calling Features

Each provider has unique features or common practices. Below we summarize helpful features and how to use them.

EE (United Kingdom)

• How to call EE abroad / how to call EE from abroad
  • To call an EE number from another country, dial +44 and the mobile number without the leading 0 (e.g., +44 7xxxx xxxxx). If you are an EE customer traveling, enable data roaming or Wi‑Fi calling to use your EE number overseas. Check EE’s roaming bundles if you need voice and data abroad.

Globe (Philippines)

• How to call overseas using Globe
  • Globe follows standard international dialing: use + or 00 then the country code and number (example: +1 for US). Globe offers international add-ons; compare their rates to VoIP options if you call often internationally.

StarHub (Singapore)

• Starhub how to call overseas / starhub free incoming call overseas
  • From a StarHub mobile, use the IDD prefix 002 plus country code and number, or dial +country code directly. StarHub and other Singapore carriers sometimes offer roaming bundles that include free incoming calls in selected zones—check your plan before travel. For cheaper long calls, consider VoIP over Wi‑Fi.

Singtel (Singapore)

• Singtel calling overseas / cheap singtel overseas call / singtel cheap overseas call
  • Singtel uses IDD prefix 001 for international dialing, but you can also dial +country code. Singtel sells international call packs that lower per‑minute rates. For cheap calls to destinations such as the Philippines, compare Singtel’s charges against VoIP services. If cost is the priority, VoIP over Wi‑Fi or a local SIM often delivers better value.

Smartone (Hong Kong)

• Smartone call forward overseas
  • To forward calls while overseas, you can use standard GSM call forwarding codes (for example, *21# to set unconditional forwarding, #21# to cancel). Smartone also supports Wi‑Fi calling for certain plans; enable this before travel to keep your number active without roaming costs.

Optus (Australia)

• How do I call Optus from overseas / how do i call optus from overseas
  • To call an Optus mobile from abroad, dial +61 and omit the leading zero (e.g., +61 4xx xxx xxx). If you’re an Optus customer traveling, check roaming options and Wi‑Fi calling availability.

Cellcard (Cambodia)

• Cellcard call oversea
  • Cellcard uses standard international dialing with + or 00 then the country code. For outgoing international calls or affordable incoming call solutions, consider local data packages and VoIP for long chats.

General tip on 1800/toll-free numbers

• Call 1800 from overseas
  • Many 1800 numbers are domestic-only and will not accept international calls. Companies that support international callers usually list a +country number or local access line for overseas customers. If the 1800 number won’t connect, try the company’s listed international contact or use a VoIP service that can reach toll-free or alternative numbers.

If you want a deeper look at VoIP alternatives and how they compare with carrier services, see our guide on how to make international calls and VoIP phone services explained.