Use Visual Studio 2017 with .Net Core SDK 3.0

Unfortunately .NET Core 3 requires MSBuild 16. Even if you enable preview versions of .NET Core in VS 2017 as others have suggested you will still get the error:

The current .NET SDK does not support targeting .NET Core 3.0. Either target .NET Core 2.1 or lower, or use a version of the .NET SDK that supports .NET Core 3.0.

If you create a global.json file and put in eg.

{
  "sdk": {
    "version": "3.0.100-preview5-011568"
  }
}

You then get shown the real problem which is:

error : Version 3.0.100-preview5-011568 of the .NET Core SDK requires at least version 16.0.0 of MSBuild. The current available version of MSBuild is 15.9.21.664. Change the .NET Core SDK specified in global.json to an older version that requires the MSBuild version currently available.`

MSBuild 16 only comes with VS 2019, so, the answer is that you CAN use VS 2017 with .NET Core 3, but only if you also have VS 2019 installed as well!

Visual Studio 2019 update

About the original answer from @GoDev :

Starting with Visual Studio 2019, the option has moved to:

Tools > Options > Environment > Preview Features

Official notes

.In VS 2017: You can just go to the Tools → Options → Project and Solutions → .NET Core and then check Use previews of the .NET Core SDK