I'm typically an early adopter of new Ubuntu LTS releases and as such I reformatted my laptop with the release hoping to get going with .NET Core right away but the posted install guide on Microsoft docs didn't work. I went back to the docs a few days later and found that the guide had been pulled. After weeks of waiting we finally got an update today! The packages should be available on 5/12/2020 (only 2.5 weeks after the LTS dropped, 🎉 great job Microsoft!)

There are several workarounds for anyone that needs to use the SDK immediately. Check them out here.

UPDATE 5/13/2020: The Ubuntu packages are live and the dependencies issues yesterday were resolved. Here's how to get it going until Microsoft updates their documentation.

wget https://packages.microsoft.com/config/ubuntu/20.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
sudo dpkg -i packages-microsoft-prod.deb
sudo apt-get update
sudo apt-get install apt-transport-https
sudo apt-get update
sudo apt-get install dotnet-sdk-3.1
Dotnet-sdk-3.1 Ubuntu 20.04 installation steps

If you had previous failed attempts you may have to purge old sources.

sudo dpkg --purge packages-microsoft-prod && sudo dpkg -i packages-microsoft-prod.deb
sudo apt-get update