Exchange 2010 On-Premise - move some mailboxes to O365?

If I have a current Exchange 2010 environment and also have the licenses for O365 Exchange Online, what would I need to do to migrate some mailboxes from some database from my Exchange 2010 on-premise server to the Exchange Online server?
Do I have to deploy a new server on-premise?

I plan to setup Data Availability Groups as well, should I do that before putting Exchange Online into the picture?
I would only have Data Availability Groups for on-premise mailboxes.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Vasil Michev (MVP)Commented:
If you want to be able to move mailboxes, you will need to establish Hybrid coexistence between the on-prem org and Exchange Online. Review the documentation on TechNet and the EDA, let us know if you have any questions:

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
garryshapeAuthor Commented:
I noticed the articles refer to Exchange 2013.
I am on Exchange 2010, should the main idea of the articles still apply and help me?
Is this article series more applicable?
Vasil Michev (MVP)Commented:
Yup, sorry. The concepts are the same, but there are some differences indeed. For the second link, you have an option to select 2010 when starting the Exchange deployment assistant.
Determine the Perfect Price for Your IT Services

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden with our free interactive tool and use it to determine the right price for your IT services. Download your free eBook now!

garryshapeAuthor Commented:
Perfect thanks
Hope I don't mess something up with ADFS
I'm assuming I need to update User Principal Names to match e-mail addresses before all of this...
Because there is a child domain in the forest that is going to have duplicate SamAccountNames with users in the parent forest.
Vasil Michev (MVP)Commented:
AD FS is not required for Hybrid. Neither it's required to have matching UPN and SMTP. But both these will make it a lot easier on the end user :)
garryshapeAuthor Commented:
Ok thanks. Is there a contact at Microsoft that could help walk me through? Or would I need to open a $499 case?
Vasil Michev (MVP)Commented:
If you have over 150 seats, you qualify for FastTrack and MS will help you a great deal with the process. Go to the FastTrack site and fill in your details:
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Office 365

From novice to tech pro — start learning today.