Verizon will launch its 5G mobile service in April, but it will only be available in two cities at first, and customers will have to pay an extra $10 a month to access it.

One bit of good news is that Verizon won't apply throttling (or "de-prioritization") to the 5G service, but that may change later on, and slowdowns will continue to apply to Verizon's existing 4G service.

Verizon today announced that its 5G network will go live on April 11 in "select areas of" Chicago and Minneapolis and eventually hit "more than 30" US cities in 2019. To use the 5G service at launch, you'll have to pay $50 for "the Verizon-exclusive 5G Moto Mod," which can be attached to a Motorola Moto Z3, a phone that Verizon sells for $480.

5G access will be available to customers who subscribe to one of Verizon's unlimited data plans for an extra $10 per month—though that $10 add-on charge will be waived for the first three months. Verizon has not said exactly how fast the 5G mobile service will be at launch.

Without the 5G service, Verizon's three unlimited plans cost $75, $85, or $95 a month for a single line and differ based on throttling policies, video quality, and mobile hotspot data limits. That means a single-line plan with 5G will cost $85 to $105 a month, plus taxes and fees.

No slowdowns on 5G, for now

With 5G, Verizon will initially be more lenient when it comes to imposing data slowdowns.

"5G data usage with the Moto Mod is unlimited with no data deprioritization," a Verizon spokesperson told Ars today.

By contrast, users of 4G LTE data with Verizon's $75 unlimited plan can be throttled "in times of congestion," regardless of how much data they use. Buying the $85 plan lets a customer use at least 22GB a month before facing possible slowdowns, while the $95 plan comes with 75GB before possible slowdowns. The plans are "unlimited" in the sense that customers don't have to pay overage fees for going over the limits.

Verizon was careful to say that "5G data usage" will be unlimited without slowdowns, so those de-prioritization thresholds will still apply to 4G usage. The de-prioritization policy "will follow your 4G plan" when you're in a 4G area, Verizon told Ars. 5G usage won't count toward the 22GB and 75GB de-prioritization thresholds, Verizon also told us.

Given the limited nature of Verizon's initial 5G rollout—and its millimeter-wave frequencies that have shorter ranges than Verizon's 700MHz 4G spectrum—customers may find themselves frequently switching between 4G and 5G, depending on where they are. The promise of "no data de-prioritization" also applies only to the Moto Mod and early launch cities. When asked if de-prioritization will be applied to future 5G devices and cities, Verizon told Ars, "we haven't determined that yet."

Verizon is also planning to sell the Samsung Galaxy S10 5G, but there's no availability date yet. You might want to wait a while before buying a 5G phone, though.

Verizon said 5G service in Chicago will be available in the Loop, the Magnificent Mile, Gold Coast, River North, and Old Town. 5G service in Minneapolis will be in Downtown West, Downtown East, and Elliot Park.

AT&T is selling a 5G mobile hotspot and 5G service in parts of 12 cities and is also misleadingly calling large portions of its 4G network "5G E."

No word on speed or latency

Verizon is already selling a "5G" home Internet service in a few cities, without any data caps or throttling. But it's based on Verizon's own version of 5G rather than the 5G NR (New Radio) global standard. With the mobile launch, Verizon is switching to 5G NR.

"5G Mobility service in Chicago and Minneapolis, and all Verizon 5G services going forward, use the NR standard developed by the 3rd Generation Partnership Project (3GPP)," Verizon's press release said.

While Verizon promises 5G home Internet speeds of 300Mbps to 1Gbps, Verizon did not say exactly what the 5G mobile speeds and latency will be.

"We can tell you that 5G Moto Mod users will experience ultra-fast speeds, be able to download and stream movies in seconds, and, due to 5G's low latency, they'll be able to video conference and collaborate remotely in near real-time," Verizon told Ars, when asked for specific speed and latency numbers. "While we have been clear that 5G service will be a significant [upgrade] over 4G LTE when it comes to speed and latency, we'll provide expected network performance information closer to launch."

Customers can pre-order the 5G Moto Mod starting March 14. The $50 price will apply for "a limited time," Verizon said. The retail price for the Mod is $350.

"To buy a 5G Moto Mod, customers must either have an active Moto Z3 on their account or purchase a Moto Z3 at the same time as the 5G Moto Mod," Verizon said. On March 14 only, customers can get a second Moto Z3 for free if they also add a new line of service. More information on the Motorola phone and 5G device is available at this Verizon FAQ.