Unlimited mobile data has become the new battlefront for telcos. Hot on the heels of a rival which launched an unlimited mobile data plan last month, virtual telco Circles.Life released its own version yesterday.

The operator's daily-rated unlimited mobile data add-on for $3, dubbed Unlimited Data on Demand, requires a basic plan of $28 a month that comes with 6GB of mobile data. The basic plan also comes with 100 minutes of local talk time and a free Caller ID feature.

Users can subscribe to the $3-a-day add-on using the latest version of the CirclesCare app on days they need unlimited mobile data.

Said Mr Rameez Ansar, co-founder and director of the two-year-old virtual telco: "The majority of users do not need unlimited data every day. We let customers choose when to boost their daily mobile data allowance and charge them a daily rate for it."

Virtual telcos do not build their own physical mobile networks, but lease them wholesale from one of the existing telcos. Circles.Life leases from M1.

Yesterday's launch comes after another virtual telco, Zero1, unveiled its $19-a-month unlimited mobile data plan last month for the first 3,000 registrations. After that, the same plan - which also comes with 200 minutes of local talk time and 200 SMS messages - costs $29.99 a month.

The prevailing rate for an unlimited mobile data plan is around $100 a month from Singtel and M1.

Other unlimited data plans

SINGTEL •Singtel offers unlimited mobile data for at least $108.80 a month, through an add-on called Data X Infinity to a basic plan. •Those who subscribe to the Data X Infinity scheme can share their data with up to three family members through a supplementary plan, which costs $10.70 a month for each line. STARHUB •StarHub does not have a plan that offers unlimited mobile data every day. Unlimited use of mobile data is available only on weekends for mobile plans that start at $24 a month for 3GB of mobile data. Its SharePlus programme - at $9.63 a month - allows the bundled data and talk time to be shared with a supplementary line. M1 •M1's mySIM3 98 unlimited mobile data plan costs $98 a month, but customers must sign a 12-month contract. ZERO1 •Zero1's $19-a-month unlimited mobile data plan is only for the first 3,000 registrations. After that, the same plan - which also comes with 200 minutes of local talk time and 200 SMS messages - costs $29.99 a month. Irene Tham

All unlimited data plans come with a "fair use" policy. This means that users will find their surfing speeds capped after they bust a certain limit.

For instance, Circles.Life caps customers' surfing speeds after they exceed 100GB of monthly mobile data. Zero1's fair use policy allows it to cap the download speed for high-definition videos after the first 3GB of data allowance is used.

For Singtel, if data use exceeds 50GB a month, a user's surfing speeds will be cut to 1Mbps. Speeds return to normal the next month.

StarHub's plans offer unlimited mobile data use only on weekends. Should data usage cross the 10GB a day threshold, StarHub customers' surfing speeds will be reduced to 1Mbps. Normal speeds will be restored the next day.

M1 has not disclosed the details of its relevant fair use policies.

Yesterday, Circles.Life also launched another add-on dubbed WhatsApp Passport. It allows unlimited roaming on WhatsApp in over 18 countries and territories including Malaysia, Indonesia, Hong Kong, Australia, the United States and Britain. Prices start from $1 a day.

Users who need unlimited outgoing calls can also pay for a new $16-a-month add-on to provide them the option.

Circles.Life also said it was behind a publicity stunt on Wednesday to promote its new unlimited data plan.

It involved vending machines at Raffles Place that dispensed a $50 note in exchange for $3, drawing long queues in the process, reported citizen journalism site Stomp.

But the event was cut short after police turned up as the organiser did not have a permit.