美国购买的 iPhone 13, iPhone 13 Pro/Max 拿到中国能不能用，美版iPhone 13在中国能不能用，是否支持中国移动、电信、联通网络？中国买的iPhone拿到美国能不能用？简单的说，当然可以用。其实苹果官网上有详细介绍，可以查看任意一款iPhone页面，在页面下方有“Frequently Asked Questions”、“常见问题解答”描述。

2G/3G/4G/5G，G指的是 Generation，“代”的意思。1G 就是第一代移动通信技术，2G、3G、4G、5G 分别指第二、三、四、五代移动通信技术的意思。我们现在正处于5G时代。

这里的G不是数据上网速度的意思，当然移动数据速度确实是一代比一代快。这个比较专业，感兴趣可以到百科或者知乎里搜索。从iPhone 5开始，所有机型都采用了4G LTE技术，从iPhone 12 开始支持5G。

简单的说，能，当然能。确切的说，看你买的哪个型号，用国内哪个运营商的服务。Apple美国官网“Frequently Asked Questions”是这么说的：

Can I use an iPhone when traveling internationally? All iPhone models are world phones, so you can use them almost anywhere. Whether you are a GSM or CDMA network customer, you can roam internationally on GSM networks in over 200 countries around the world. Availability of LTE data varies in some countries and depends on carrier support for certain LTE radio frequencies. Contact your wireless carrier for more information regarding international roaming policies and rates.

同样的答案：可以。Apple中国官网“常见问题简答”是这么说的：

iPhone 能够与全世界任何 SIM 卡或任何运营商配合使用吗？ 目前 apple.com 出售的 iPhone 机型可使用来自兼容运营商的 nano-SIM 卡，并且支持全球众多 4G LTE 网络。请联系服务提供商了解详情。 我可以在国外使用我的 iPhone 吗？ 我可以在国外使用我的 iPhone 吗？ 可以。iPhone 可在全世界支持 GSM 的网络中使用。因为 apple.com 出售的 iPhone 无需合约，所以你可以在目的地国家或地区的当地运营商处购买 SIM 卡和服务。或者你也可以向国内的运营商咨询有关国际漫游资费的信息。

Are there differences between an iPhone for AT&T or T-Mobile and an iPhone for Sprint or Verizon? iPhone offers the same innovative features regardless of the wireless carrier you choose. If you choose AT&T or T-Mobile as your wireless carrier, your iPhone will use either 3G or 4G LTE cellular technology for data services and voice services. iPhone can roam internationally on many GSM carriers around the world. If you buy an iPhone with AT&T or T-Mobile, it will not work if you switch to Sprint or Verizon.If you choose Sprint or Verizon as your wireless carrier, your iPhone will use CDMA cellular technology for voice and data services. If you buy an iPhone with Sprint or Verizon, it will work on AT&T or T-Mobile. An iPhone activated on Sprint or Verizon also has the ability to roam internationally on GSM networks. For details on LTE network support, please see www.apple.com/iphone/LTE. What does “SIM-free” mean? “SIM-free” means your iPhone doesn’t ship with a carrier SIM card. The SIM-free iPhone sold on apple.com and at the Apple Store is unlocked. That means you’re free to use a SIM card from any carrier that provides service for iPhone.

简单的理解:

所以，如果是在AT&T、T-Mobile、Sprint、Version或者Target、Best Buy、Sam’s Club等地购买iPhone也是一个道理。

原因是运营商有一些绑定的分期付款计划选择，如2年无息分期、每一年或者两年换新iPhone等。Sprint 2-Year Contract、AT&T Installment Programs、Verizon Device Payment Program、等。如果选择了这些计划，那么买到的iPhone是有锁的。如果 Pay in full, One-time payment ，一次性全款付清，是unlocked 无锁的。

When I buy an iPhone from apple.com, is it tied to a carrier or does it come “unlocked”? Nearly all iPhone models sold on apple.com are “unlocked” — which means your iPhone isn’t tied to a single carrier. Your iPhone will only be tied to your carrier if you choose carrier financing from AT&T or Sprint.