How do I connect my old Mac to my new Mac without using the internet?

Migration Assistant does not use the internet.

Here are a few articles that should help you set up & perform your migration:

https://support.apple.com/en-us/HT204350

https://support.apple.com/guide/imac/transfer-your-data-apd6a937e818/2020/mac/11

There are basically three ways to connect your Macs for migration:

• Connect both computers to the same local network via Wi-Fi (wireless) and/or Ethernet (wired).
• Connect both computers to each other using a Thunderbolt, FireWire, or Ethernet cable. (USB generally does not work for this purpose.)
• Make a Time Machine backup of your old Mac on an external drive. Then connect the drive to your new Mac and restore the TM backup to your new Mac.

Silverfox155 wrote:

does migration assistant use the internet when migrating data from an old Mac to a new Mac?

No. An Internet connection is not required.

And is there away to connect the two Macs without using wi-go?

You can use a cable to connect the two to each other, but the most convenient option is to have both of them on the same wireless network. They will communicate with each other through the router they're connected to.

As John Galt pointed out, you can connect the two Macs with a cable. Some have reported that doing that can be tricky. I have done numerous such migrations and have always done it with an external drive. First the external drive is used to make a complete backup of the old computer. You can use Time Machine or a "cloning" commercial tool (examples include CCC, SuperDuper, TechTool Pro, there are many; Disk Utility can also be used).

One benefit of using the external backup drive is that you can continue using the external backup drive with either computer after the migration is confirmed to be successful.

Then when you activate the migration on the new Mac you select the option to migrate from a backup external drive. This is much faster than WiFi in most cases, and more reliable. Connecting the two Macs with a cable can be reliable and fast also depending on the type of cable.

Since you have been given all sorts of advice, I will add mine, for what it's worth. I am assuming that you are wanting to connect the two computers so you can use Migration Assistant to transfer your date. Apple's instructions are clear on this , except for one thing. They say you can use a wireless connection. Yes, you can. But it will be slow and will often corrupt the data being transferred or result in some data being lost. I very strongly recommend that you ONLY use a wired USB connection. I have done that a number of times. It is much faster and no corruption or loss of data will occur.