Tim Coalson is a Senior Consultant in the Transformation Practice at ThreeWill. Tim has been developing solutions on the SharePoint platform for over 15 years and has been a developer/consultant for over 30 years. Tim has been involved in migrating SharePoint on-premises farms to the Microsoft Cloud, Power Apps, and Power Automate (aka Flow) which are part of the Microsoft no code/low code solutions.
Introduction
Migrations are painful. I wish I could tell you otherwise. In some ways it might be likened to a house move. You generally choose to move from one house to another because the new house will better suit your needs, but there is some investment and work involved in making the move. Sometimes you probably question whether the move is worth it as you get involved in the work to make it happen, but you remind yourself why you started this move and press forward
A Migration to SharePoint Online Is Like Buying a New House
Until you really dig in and get started, you forget how much stuff and how much investment has been put into your old house. While the possibilities of creating a great future in the new house is possible and exciting, there is a lot of work to get there. Problems you solved at the old house may or may not fixed or available in the new house. And then you must figure out how to move the stuff from the old house. You have to think ahead to determine where things will go and then physically move it to the appropriate location. Some stuff in the old house might not fit or will be out of place. And there will be some transition time where neither the old house nor the new house will be exactly like you want it. But, in the end, the new house will be worth the investment as you enjoy the new features and benefits that make the pain of the move worthwhile.
Similar to the planning involved in moving from one house to another, there is a similar need to plan your migration from SharePoint on-premise to SharePoint Online. As I mention things that need to be considered when migrating to SharePoint online, you will be reminded of the analogy and determine to move forward in anticipation of the benefit you expect to receive.
How to Prepare to Migrate to SharePoint Online
Based on my personal experience and collective experience within ThreeWill, I’ve identified a number of steps that need to be considered. In future posts, I may elaborate on some of these areas, but the list below provides a good, high-level roadmap that should be considered for any SharePoint on-premise to SharePoint Online (SPO) migration:

Steps to Migrate to SharePoint Online
1. Manage the upcoming change
Significant changes to an organization need to be communicated appropriately and training provided to make the transition as smooth as possible.
2. Analysis of the source environment
There are most likely features and other mission-critical functionality in the current environment. Work with your organization to determine these features/functionality to minimize the impact during the migration. Identify any features/functionality that will NOT migrate based on the selected migration tool and determine how these will be handled.
3. Determine an appropriate archive strategy
Some sites/data may not need to be migrated but may need to be retained/archived for legal or other reasons.
4. Plan the future-state environment
How do you want the user-experience to be and how does the data/functionality in the old environment map to the new environment? What features are available in SharePoint Online (SPO) that can be leveraged to create a better user experience?
5. Select an appropriate migration tool or tools
Select a migration tool or combination of tools that will best fit your migration requirements. It is helpful to know that migrations tools are not all created equal.
6. Pilot your migration with a representative sampling of sites
There are several factors that will impact how quickly and accurately your data will migrate, so run some tests to set accurate expectations and to create a more accurate plan for the remainder of the site migration.
7. Plan your migration schedule
Based on what you learned from your migration Pilot, create a migration plan that is realistic. Both training and communication need to be tightly integrated with this plan.
8. Perform the migration
Migrations are normally performed in waves (smaller subsets of sites) and generally performed in 2 phases, where an initial migration is done followed by one or more delta or incremental migrations to keep the data updated until the production cut-over.
9. User Acceptance Testing
When hundreds or thousands of sites are migrated, it is impossible for the migration team to know every detail about these sites and be able to validate the migration. So, it will be critical for the current site owners, or others who are familiar with the current sites, to validate everything works and looks correct in the new environment. The migration team can validate data counts in lists and libraries, but cannot validate InfoPath forms, workflows, and other features.
10. Remediate issues
It is inevitable that there will be some data that does not migrate over correctly and some web pages that will not display correctly. Many customizations that were available in On-Premise are not supported “as is” in SPO so remediation (fixing stuff) will be necessary.
11. Final Delta/Incremental Migration
In anticipation of the production roll-out of the site, a final incremental migration is executed to pick up any last changes. At this point, the old site is made read-only or inaccessible and a link or redirect is provided to point users to the new environment. Communications have been ongoing, so this is not a surprise to the user, but an eager anticipation of the new features available in the new environment.
Conclusion
Hopefully you can see from the high-level steps listed above that a migration is not trivial. However, with a good plan and associated communications and training, a migration can be successful so that you can experience the benefits you anticipated in moving to SharePoint Online.