It’s official. All four major carriers now offer “unlimited” mobile data plans. Verizon has Go Unlimited, Beyond Unlimited, and Above Unlimited. AT&T offers Unlimited & More, and Unlimited & More Premium. T-Mobile offers Unlimited, and offers Unlimited 55+ for people over 55. And Sprint rounds out the group with its Unlimited Freedom offer. There’s only one problem. None of these plans actually offer unlimited data. They offer mostly unlimited data with specific restrictions. “Let me explain … No, there is too much. Let me sum up.”

• Want the most unlimited data? Verizon’s got you covered.
• Is live TV important to you? AT&T Unlimited & More might be worth a look.
• Traveling internationally? T-Mobile Unlimited is a safe choice.
• Looking for the cheapest plan? Sprint Unlimited Freedom.

Unlimited

Unlimited? Inigo Montoya said it best: “You keep using that word. I do not think it means what you think it means.” Every major wireless provider’s plans feature unlimited talk, unlimited text, and unlimited data. However, many “unlimited data” plans have a 4G/LTE data cap. Once you hit that point, you’re still able to access data, but your speed is throttled, often to 3G (or worse). Wireless carriers often refer to this as “re-prioritization.” You can refer to it as “limits for unlimited plans.”

So, without further fanfare or any more Princess Bride quotes, here’s what you need to know about “unlimited” plans from the four major carriers:

Verizon

Cost for a Single “Unlimited” Line: $75 – $95/month (plus taxes and fees).Carrier Details.

The Best Unlimited Data Plan: The Verizon Above Unlimited plan offers 75GB of 4G data per month, along with 20GB of hotspot allowance (which is super handy when you need the full capabilities of your laptop while stuck in crosstown traffic). At $95/month (plus taxes and fees), it’s the most expensive unlimited plan out there, but it also offers the most data.

An Added Benefit: This plan also includes 500GB of Verizon Cloud storage.

The International Plan: With this plan, you can add international data to your plan for $10/day per device. No separate plan is needed.

Over the Cap? “We may manage your network usage to ensure a quality experience for all customers, and may prioritize your data behind other Verizon customers during times/places of network congestion.”

AT&T

Cost for a Single “Unlimited” Line: $70+/month (plus taxes and fees). Carrier Details.

The Best Unlimited Data Plan: The AT&T Unlimited & More Premium (at $80/month) costs $10/month more than the AT&T Unlimited & More package but is worth the upgrade. In addition to 1080p streaming (the base plan only allows 480p streaming), this plan also includes 15GB of hotspot allowance. FYI 1080p is HD quality and 480p is standard definition television quality. Importantly, depending on the resolution of your screen, you may not be able to tell the difference. That said, if you are using the plan with a laptop or late-model video monitor, pony up for the 1080p plan.

An Added Benefit: Both AT&T plans include 30+ channels of Live TV, but the Premium package also includes one of seven “music, movie, or entertainment perks” like HBO, Cinemax, Showtime, or Amazon Music.

The International Plan: Like Verizon, AT&T will let you add international data to your plan for $10/day per device.

Over the Cap? “After 22GB of data usage on a line in a bill cycle, for the remainder of the cycle AT&T may temporarily slow data speeds on that line during times of network congestion.”

T-Mobile

Cost for a Single “Unlimited” Line: $70+/month (no taxes or fees). Carrier Details.

The Best Unlimited Data Plan: T-Mobile has two unlimited data offerings. Both offer 50GB of 4G data, but T-Mobile ONE Plus (which costs $80/month) offers 10GB of 4G hotspot data and full 1080p streaming.

An Added Benefit: Always in the air? T-Mobile ONE Plus includes unlimited in-flight Wi-Fi on Gogo-enabled flights. If you fly as much as I do (I often say my home is Terminal 5 at JFK), those savings add up. Also nice: unlimited HD streaming (effectively rendering the 50GB data “cap” moot).

The International Plan: While the T-Mobile ONE Plus plan includes 2x international data speed (vs. the base T-Mobile ONE plan), you can upgrade to T-Mobile ONE Plus International, which offers the same boosted international data speeds as well as unlimited international calling, unlimited 4G LTE in Mexico and Canada, and – here’s the big one – unlimited 4G LTE mobile hotspot data. This plan costs $95/month.

Over the Cap? “On all T-Mobile plans, during congestion, the small fraction of customers using >50GB/mo. may notice reduced speeds until next bill cycle due to data prioritization. Video typically streams at DVD quality (480p). Tethering at max 3G speeds. Pricing reflects AutoPay discount; without AutoPay, $5 more/line.”

Sprint

Cost for a Single “Unlimited” Line: $60/month (plus taxes and fees). Carrier Details.

The Best Unlimited Data Plan: Sprint has only one option: Sprint Unlimited Freedom, which costs $60/month (plus taxes and fees). This plan includes 23GB of 4G data and 10GB of mobile hotspot. There aren’t too many frills, but it’s the cheapest unlimited plan out there.

An Added Benefit: Every Sprint account also includes one Hulu (with limited commercial interruptions) account, which normally costs $7.99/month.

The International Plan: Sprint’s international plan is the most convoluted of the bunch. Unlimited texting and 2G data are included at no additional cost, but calls cost 20 cents/minute. If you’re going to Canada or Mexico, you can bump up to 4G data for $2/day or $10/week. “Most destinations” will cost $5/day or $25/week, while “other destinations” will run you $10/day or $50/week. Confused? So am I. You can try to figure it out for yourself.

Over the Cap? “For these customers, if they use more than 23GB of data during a billing cycle, they will be prioritized on the network below other customers for the remainder of their billing cycle, only in times and locations where the network is constrained. (These customers will still be able to use unlimited amounts of data without the worry of overage charges.)”

Choosing the Right Plan

Assuming you could afford any of these plans, which is best for you? The answer is unchanged from the beginning of the cellphone era. It comes down to which carrier offers the best coverage for your particular needs. You can be on the best phone on the best network and find yourself with one bar of signal and an unusable connection. You can be on the cheapest phone on the least expensive carrier and enjoy an unbuffered streaming video. Choosing the carrier that works best where you are (and where you tend to travel) is still the determining factor. After all, what good is “unlimited” data if you can’t connect?