Bucking the trend of shared data plans, T-Mobile is offering its customers something they haven’t seen in a while: truly unlimited data.

That’s right, T-Mobile said Wednesday that it will be offering limitless and throttle-less data plans — and for its HSPA+ 4G network, no less — starting on Sept. 5.

The unlimited data plan will cost $20 per month when added to a Value voice and text plan or $30 per month when added to a Classic voice and text plan. Value plans do not include smartphone subsidies, but have lower monthly rates.

That means that unlimited plans will start at $69.99 and $89.99, which is cheaper than the monthly cost of Sprint’s unlimited data plan, which runs on a 3G network.

The company will continue to offer its current data plans in addition to the unlimited option.

It is worth mentioning that T-Mobile’s HSPA+ networks is not considered by some to be truly 4G, though it can reach speeds of up to 42 mbps in some coverage areas. T-Mobile is expected to roll out LTE capability by the end of the year.

The plan could be a major boost for those who buy unlocked iPhones, who may be looking for an unlimited, 4G option.

The Verge reports that the plans will not work with hotspots, and that the company was unable to say if the same 4G plans would apply to LTE coverage.

T-Mobile is not the only company offering an unlimited 4G plan Wednesday. MetroPCS is offering a promotional unlimited data plan for $55 starting on Thursday on its LTE network. The plan is available for a limited time, which The Wall Street Journal reported could last three to six months. At the end of the promotion, the unlimited data plan goes to $70 per month.

Related stories:

Upcoming iPhone has smartphone buyers holding off, report says

Verizon Wireless to offer free voice and texting, boost cost for data use

Smartphone payment space packed with competition