A Microsoft 365 tenant-to-tenant (T2T) migration may be one of the biggest and most complex migrations your organisation will ever undertake. Those in the know understand that it’s also the perfect opportunity to maximise future returns on your technology investment.
Our skilled tenant migration team has created this Cloud Essentials Step by Step Guide to help you capitalise on that opportunity, regardless of whether you’re migrating due to a merger, acquisition, divestiture or re-organisation drive.
Over the course of this guide, you’ll learn how to start navigating the immediate challenges of a T2T migration, while keeping an all-important eye on optimising your target environment and streamlining your end user experience. Done right, this approach should set you up for a smoother and more successful T2T migration with far-reaching benefits that extend well beyond your final cutover date.
Those benefits include:
Sound good? Let’s dive in.
Tenant-to-tenant migrations often have exceptionally tight timelines, but believe us when we say: it’s worth your while to look before you leap. In fact, if we could give only two pieces advice for anyone facing an upcoming tenant-to-tenant migration, they would be:
Getting a migration right requires a comprehensive understanding of each tenant involved. Questions to ask include:
In order for your tenant-to-tenant migration to pay off on all possible fronts, you also need to think beyond the immediate requirements of the migration. Good questions to ask include:
“Cloud Essentials understand the importance of carrying out a project the right way, no matter the size of it. They don’t take any short cuts.”
In our experience, the following three areas are the most likely to make or break your tenant-to-tenant migration (both in terms of short-term successes and long-term benefits). Getting to grips with them in advance – and knowing which pitfalls to look out for – significantly boosts your ability to control for positive migration outcomes.
The Cloud Essentials migration team have been busy working on over 18 Microsoft 365 tenant-to-tenant migrations between 2024-2025.
– 500 – 10,000+ mailboxes
– High value and sensitive data
– Complex, regulated industries
With all the technical considerations of tenant-to-tenant migrations, it’s easy to overlook the human element. Ironically, keeping users connected, content and productive is one of the hallmarks of a successful migration, and of primary importance to most (if not all) businesses.
A good rule of thumb is to minimise the amount of user intervention a migration requires. The less users need to do, the lower their chances of getting it wrong, making for smoother migration experience (for everyone).
That doesn’t mean falling into the trap of defaulting to the lowest common denominator in terms of your target tenant’s tools and technology, however. With a little guidance, a migration can be the perfect opportunity to introduce users to new capabilities that will take their post-migration work experience to the next level.
“This was a smooth migration with very little impact on the business during the changeover, we would definitely use Cloud Essentials again if we need to do another migration!”
In terms of user-focussed migration planning, we strongly recommend considering the following:
Co-existence is a way to enable teams from source and target tenants to communicate and collaborate as one, long before their environments have been fully integrated.
It’s a real productivity saver for a number of reasons, including:
For co-existence to go smoothly, you’ll need to add the following to your migration planning:
Pro tip: In our experience, it’s best to migrate user-owned content first (mailboxes/ OneDrive for Business), followed by collaborative content (Teams/SharePoint). Just remember to let users know how to switch between tenants in the interim (unless you enjoy a lot of support calls).
Client: Global facilities company operating in over 50 countries
Challenge: A complex divestment required seamless co‑existence from day 1 for over 1,500 employees across 30,000 client locations. The migration involved consolidating three domains—all while maintaining uninterrupted business‑as‑usual operations.
Success: A new, independent Microsoft 365 tenancy was established with a seamless transition that kept disruption to a minimum, and the project was delivered ahead of schedule—resulting in valuable licence cost‑savings.
We recommend kicking off your communication campaign around 30 days before the migration date. Start with an overview of what’s approaching and fill in more details as key dates approach.
Remember, too little information will leave users feeling unsettled and uncertain, but too much can be equally problematic, increasing the chances of critical messages being overlooked (or outright ignored).
The wrong tool can derail a migration before it even gets started. But with so many options out there, how do you tell which migration tool is right for you?
We won’t pretend that it’s easy – particularly if you’ve never travelled this road before. To help narrow your choices down, here is our list of essential capabilities to look out for:
Pro tip: We’ve yet to find a single tool that meets the needs of every project we encounter. It’s definitely worth taking your time to find the best fit for your particular needs. Don’t want to go it alone? When it comes to finding a partner, experience talks. Look for a migration partner with tried and tested methodologies supported by runbooks that cover all aspects of the migration, including stakeholder communication.
“This has been very refreshing. And Cloud Essentials have been not just an implementer, but a trusted partner. They’ve effectively become our ‘SharePoint arm’ within the company. They haven’t taken a cookie-cutter approach with something from another environment, but have genuinely wanted to find the best way to help us.”
Architecting your target tenant for a seamless – yet future-proof – transition is an art. It takes both precision and creativity to find the perfect balance of what you have, what you need, and what you want in way that optimally supports your future growth trajectory.
This is another area in which it may be tempting to default to the lowest common denominator between tenants. Be warned: the consequences for taking this “short cut” (particularly around security and governance) invariably outweigh any timesaving benefits there might be.
Instead, we strongly suggest working your way through the following questions (at the bare minimum) to get your architectural planning off to a well-considered start.
Pro tip: Where possible, we highly recommend separating out your Azure workloads to be migrated after the initial migration of user-related content and Office 365 workloads. It’s a small change, but can have a big impact on streamlining your migration and minimising business disruption.
We specialise in complex tenant-to-tenant migration for Office 365 workloads. We offer fully managed, end-to-end migrations within a fixed budget and timeframe. We understand that you need reliability in a time of great change.
Acquire, divest, consolidate. We love a good migration challenge. Get in touch with our experts to discuss your project.
