giga vs ZYM

Shopping around for a SIM-only plan? You have plenty to choose from in Singapore, and on the surface they can look pretty similar.

Two things are worth checking before you commit: what happens to the data you don't use, and how often your roaming allowance comes back. Miss those and you're paying for data that disappears at the end of the month.

That's where giga and ZYM Mobile part ways. giga puts free rollover on every plan and refreshes your roaming every month, so what you've paid for doesn't quietly disappear. ZYM doesn't list rollover on any of its plans, so local data you haven't used by the end of the month is gone. Its roaming splits in two: a monthly allowance that refills, and a much bigger one-time pot that has to last 365 days.

giga vs ZYM: A Quick Overview

Network: giga runs on the StarHub network and ZYM runs on the Singtel network. This is the one difference you cannot undo later by changing plan.
Data rollover: giga carries unused data forward for two more renewal cycles, on every plan it sells. ZYM does not list data rollover on any of its plan pages, so unused local data does not carry forward. Some comparison sites show rollover on selected ZYM plans, so check the plan page before you sign up.
Roaming: giga's allowance refills every month on every plan. ZYM's refills monthly too, but only the smaller APAC allowance. Its large Malaysia, Indonesia and Thailand pot and its worldwide bonus are granted once at activation and expire 365 days later.

What Is giga?

giga is StarHub's digital mobile brand, and it runs the whole thing from an app. There are no shops and no service counters. You sign up in the giga app or on the giga website, and your line activates in a few taps. Everything after that happens on your phone, from checking your data to buying a roaming pack.

Because giga is a StarHub brand, your traffic runs over StarHub's 4G and 5G network. giga's mobile plans are all SIM-only, split between 4G and 5G. Most are billed monthly, and three are billed every six months. None of them locks you into a contract, and none carries an early termination fee. Around the plans sit gigaRoam for topping up roaming, gigaBuddy for a second device, and gigaAI on the flagship plan.

What Does giga Offer?

Every giga plan includes free data rollover, a monthly Asia roaming allowance, free caller ID and eSIM. From 400GB upward the 5G plans add monthly international roaming across 48 destinations. Local minutes and SMS scale with the plan, from 300 of each on the entry plans up to 1,500 on the 1TB plan. IDD is not bundled.

Free Rollover Data on Every Plan

Your unused data carries forward for another two renewal cycles, capped at your plan's own allowance at any one time. A 300GB plan can hold up to 600GB, a 500GB plan up to 1TB, and the 1TB plan up to 2TB. Six-month plans carry forward for one cycle instead of two.

giga puts it on every plan, including both 4G plans, and it needs nothing from you: no claim, no toggle, no top-up before a deadline. A month spent mostly on office Wi-Fi leaves you more data for the month you travel.

gigaFLEX+

gigaFLEX+ is giga's flagship plan, and it is open to everyone. There is no age restriction and no eligibility test.

It runs at $19.90 a month, currently $13.90 for the first 12 months. Promo ends 31 Aug.

It also carries three things the other giga plans do not:

Free gigaAI: unlimited tokens and unlimited web searches each month, up to 300 images and 10 deep research runs, with no separate AI subscription to pay for.
Free bubble tea monthly: one PlayMade drink every month for as long as you hold the plan.
Free rollover: the 800GB allowance stacks to 1.6TB, and that data works across Singapore, Malaysia, Indonesia and Thailand.

Free Roaming Across 48 Destinations

giga includes roaming on every plan, and it refills every month for as long as you hold it. All plans carry Asia roaming across Malaysia, Indonesia, Thailand, India and South Korea, from 2GB a month on the entry 4G plan up to 16GB on the 1TB plan. The 5G plans from 400GB upward add international roaming across 48 destinations, from 6GB to 12GB a month.

giga also names the network to connect to in each Asia destination. That is Maxis or U Mobile in Malaysia, Indosat or Telkomsel in Indonesia, True Move or DTAC in Thailand, SK Telecom or KT in South Korea, and Airtel, BSNL or Vodafone Idea in India. If your trip outlasts the included allowance, gigaRoam sells top-up packs.

What Is ZYM?

ZYM Mobile is a Singapore MVNO operated by Handphoneshop Pte Ltd, a subsidiary of mDR Limited, which is listed on the Singapore Exchange. It sells no-contract postpaid SIM-only plans online and through reseller outlets around the island.

New subscribers are asked to stay for a minimum of two months before porting out.

What Does ZYM Offer?

ZYM's plan family is built around travel, and almost every plan is named for it: Roam SAVER at the entry level, then Roam PLUS, Roam SMART, Roam ECO and Roam POWER. One data-only plan, Flexi DUO, sits outside the range. Local data allowances are monthly, and none of ZYM's plan pages lists a rollover benefit, so whatever you do not use does not carry forward. A fair usage policy caps all plans at 300 SMS a day.

Roaming Allowances

ZYM runs two roaming allowances side by side, and they work differently. The first is monthly and resets on the 1st, from 5GB across six APAC destinations on Roam SAVER up to 30GB on Roam SMART. The second is a one-time pot granted at activation and valid 365 days, from 100GB for Malaysia on Roam SAVER up to 1,000GB across Malaysia, Indonesia and Thailand on Roam SMART, with a worldwide bonus across 198 destinations on the higher plans. Spend that second pot early and it does not come back.

As with giga, the allowance only applies if you connect to ZYM's listed partner network once you land.

IDD and Call Inclusions

ZYM bundles international dialling into the plan, which giga does not. Incoming calls, incoming SMS and caller ID are free.

Detailed Breakdown: giga vs ZYM

Network Coverage & Speed

Because the two brands sit on different host networks, the fairest read comes from Opensignal, which measures what users actually experience instead of quoting the telcos' own claims. Its July 2026 Singapore report is the latest edition, covering the four nationwide operators.

Download speed: StarHub wins outright on 172.7Mbps, ahead of Singtel on 164.4Mbps.
Upload speed: StarHub wins outright on 25.3Mbps, ahead of Singtel on 24.2Mbps.
Video experience: StarHub wins outright on 74.3 points, ahead of Singtel on 73.2 points.
5G download speed: StarHub shares the award on 302.4Mbps, ahead of Singtel on 294.8Mbps.
Reliability and consistent quality: Singtel leads, on 927 points against StarHub's 826, and on 84.7 per cent of tests against 78 per cent.
5G reach: Singtel leads on coverage, 9.5 out of 10 against 9.0, and on how often you are connected to 5G, 79.9 per cent against 70 per cent.
Awards overall: Singtel takes Best Network, on the strength of reliability and 5G reach. StarHub takes every speed and video award outright.

TLDR: the wins are split, with StarHub, Singtel and M1 each taking something, so neither network will feel different while you scroll. The gap only shows if you tether a laptop or work off mobile data all day.

Overseas Roaming Features

The size of each allowance matters less than how often it refills.

How often it refills: giga's whole allowance resets every month, so 3GB used in March still leaves you the full allowance in April. ZYM's monthly APAC allowance resets too, but the larger pot beside it does not, so 3GB drawn from that in March is 3GB you no longer have in December.
How you get it: giga's monthly plans refill each month, while its six-month plans give you the full allowance at the start. The 3TB plan at $109.90 comes with 66GB of Asia roaming and 48GB of international roaming for the whole six months. ZYM grants its one-time pots the same way, though giga still rolls over your unused local data.
Which plans include it: both put roaming on every plan. giga covers five Asian destinations from its entry 4G plan up. ZYM's entry plan starts at six APAC destinations, and its Flexi DUO data plan covers Malaysia only.
Who each one suits: a weekend in Johor most months, plus the occasional longer trip, favours giga. Two trips a year to Europe favours ZYM.
How far it reaches: giga covers five Asian destinations on every plan, and 48 international destinations on the 5G plans from 400GB up. ZYM reaches more of the world, and its one-time pots for the neighbouring markets are much larger.

Number Porting

Both brands let you keep your number, as required of every Singapore telco. The difference is turnaround and commitment.

On giga you choose Port-in Number during sign-up, receive a SIM with a temporary number, and the port is processed on the next working day. You can also sign up now and port in later if you are still serving out a contract elsewhere. ZYM states that porting in usually takes up to five working days, and asks subscribers to stay at least two months before porting out again.

Add-Ons and Top-Ups

Both brands sell extra roaming rather than cutting you off when the included allowance runs out, and the packs are shaped differently.

giga sells gigaRoam packs that activate on their own once you are overseas. APAC is 1GB for $5, valid five days across 14 countries. Global is 1GB for $15, valid fifteen days across 48 destinations. Existing customers can also add the gigaBuddy data-only plan for a tablet or portable router, at $3.97 a month for 10GB.

ZYM sells ZYM Travel packs by region and by country. Asia 9 is 4GB for 30 days at $12, Asia Plus 24 is 6GB for 30 days at $15, and Global Pro 198 is 6GB for 30 days at $30. Country packs start at 3GB for seven days at $5 for Malaysia, Thailand or Indonesia, and run up to 30GB for 30 days at $16 for Malaysia. IDD is sold as an add-on too, at $3 for 30 minutes to 16 in-demand destinations, or $10 for 30 minutes to the wider list.

giga's packs are small and short, built to bridge the last few days of an included allowance. ZYM's are larger and run a full 30 days, which suits a single long trip better, and its Malaysia packs go further than anything giga sells as a top-up.

giga vs ZYM: Plan Pricing

All prices below are correct at the time of writing.

giga

Monthly Plans

100GB, 4G, $10.90: 300 minutes and 300 SMS, 2GB Asia roaming, free rollover.
200GB, 4G, $12.90: 300 minutes and 300 SMS, 4GB Asia roaming, free rollover.
gigaFLEX+, 800GB, 5G, $19.90, currently $13.90 for the first 12 months: 1,000 minutes and 1,000 SMS, 12GB Asia roaming, 10GB international roaming, free gigaAI, free bubble tea monthly, free rollover
300GB, 5G, $15.90: 300 minutes and 300 SMS, 8GB Asia roaming, free rollover.
400GB, 5G, $18.90: 800 minutes and 800 SMS, 10GB Asia roaming, 6GB international roaming, free rollover.
500GB, 5G, $20.90: 1,000 minutes and 1,000 SMS, 12GB Asia roaming, 10GB international roaming, free rollover.
1TB, 5G, $28.90: 1,500 minutes and 1,500 SMS, 16GB Asia roaming, 12GB international roaming, free rollover.
400GB, 5G, $11.90, for ages 15 to 29: 800 minutes and 800 SMS, 12GB Asia roaming, 4GB international roaming, free rollover.

6-Month Plans

600GB, 4G, $59.90 for six months, about $10.00 a month: 1,800 minutes and 1,800 SMS, 12GB Asia roaming, free rollover.
3TB, 5G, $109.90 for six months, about $18.32 a month: 6,000 minutes and 6,000 SMS, 66GB Asia roaming, 48GB international roaming, free rollover. Singapore, Malaysia and Indonesia data.
6TB, 5G, $139.90 for six months, about $23.30 a month: 9,000 minutes and 9,000 SMS, 96GB Asia roaming, 72GB international roaming, free rollover. Singapore and Malaysia data.

On the six-month plans the price covers the whole six months, and rollover carries forward one cycle instead of two. Base data covers Singapore on the 300GB plan, Singapore and Malaysia on the 5G plans from 400GB up, Singapore, Malaysia, Indonesia and Thailand on gigaFLEX+, and Singapore, Malaysia and Indonesia on the 3TB six-month plan. giga marks the 200GB 4G plan as its recommendation for seniors.

ZYM

Flexi DUO, 77GB, 4G: data only, shared between Singapore and Malaysia, plus a one-time 100GB Malaysia allowance valid 90 days. No outgoing minutes or SMS.
Roam SAVER, 200GB, 4G, $7.77: 300 local minutes, 100 SMS, 100 IDD minutes, 5GB monthly APAC roaming, 100GB one-time Malaysia roaming.
Roam PLUS, 600GB, 4G, $10.10: 5G+ for the first 180 days, 1,000 local minutes, 100 SMS, 300 IDD minutes, 15GB monthly APAC roaming, 600GB one-time regional roaming.
Roam SMART, 700GB, 5G+, $15.10: 2,000 local minutes, 100 SMS, 500 IDD minutes, 30GB monthly APAC roaming, 1,000GB one-time regional roaming.
Roam ECO, 550GB, 5G+: 1,000 local minutes, 100 SMS, 300 IDD minutes, 20GB monthly APAC roaming, 700GB one-time regional roaming.
Roam POWER, 700GB, 5G+, $22.10: 2,000 local minutes, 100 SMS, 500 IDD minutes, 28GB monthly APAC roaming, 800GB one-time regional roaming.

TLDR: ZYM is cheaper to start. giga's unused data carries over, so you keep what you have already paid for.

giga vs ZYM: Which Should You Choose?

Choose giga for:

Free gigaAI in the plan. No other Singapore telco bundles an AI assistant with a mobile line, and gigaFLEX+ includes unlimited tokens and unlimited web searches each month, up to 300 images and 10 deep research runs, with no separate subscription to pay for.
Fastest network. StarHub, giga's host network, took Opensignal's Download Speed award outright in its July 2026 Singapore report on 172.7Mbps, ahead of Singtel on 164.4Mbps, and it took the Upload Speed and Video Experience awards outright too.
Rollover on every plan. Unused data carries forward for two more renewal cycles on every plan giga sells, both 4G plans included, with nothing to claim and no toggle to switch on.
Free bubble tea every month. gigaFLEX+ comes with one PlayMade drink a month for as long as you hold the plan, and gigaSurprise drops (free roaming data, free sms, free calltime, and monthly giveaways with the brands we work with) and birthday treats (free data, free sms, free calltime) land in the app through the year on top of that.
A faster switch across. You choose Port-in Number at sign-up and giga processes the port the next working day, against the five working days ZYM quotes.
Everything in one app. Sign-up, porting, data checks and roaming top-ups all happen in the giga app, with no shops and no service counters to visit.
Roaming that comes back every month. Asia roaming refills monthly on every plan, and the 5G plans from 400GB upward add monthly international roaming across 48 destinations.

Choose ZYM for:

Lower entry price. You want the lowest monthly bill you can find.
Long trips. You take one or two long trips a year and would rather have a big annual roaming pot than a monthly allowance.
Worldwide reach. You travel well beyond Asia, since ZYM's worldwide roaming reaches 198 destinations against giga's 48.
IDD in the plan. You make regular IDD calls from Singapore and want those minutes built into the plan.
In-person sign-up. You would rather sign up in person at a reseller outlet than online.

giga vs ZYM FAQs

Which telco is better, giga or ZYM?

giga is the stronger all-rounder. Rollover on every plan means the data you have paid for does not vanish at the end of the month, Asia roaming refills every month on every line including both 4G plans, and gigaFLEX+ adds gigaAI and a monthly PlayMade bubble tea that no other Singapore telco puts in a mobile plan. ZYM is the better fit if the lowest possible monthly bill is the deciding factor, or if you take one or two long trips a year well beyond Asia, where its one-time roaming pots reach further.

Do giga or ZYM require long-term contracts?

Neither uses a fixed-term contract. giga's plans run month to month with no early termination fee. ZYM plans are also no-contract, though it asks you to stay at least two months before porting out.

Do ZYM and giga offer 5G plans and eSIMs?

Both do. giga's 5G plans start at 300GB for $15.90 a month. ZYM's 5G plans start with Roam PLUS at $10.10 a month. It has launched eSIM with a published device compatibility list, though parts of its own plan FAQ still describe physical SIM only.

Can I keep my number when switching to ZYM or giga?

Yes, with both. On giga you select Port-in Number during sign-up and the port is processed the next working day. ZYM states that porting in usually takes up to five working days.