How to migrate from Slack to Microsoft Teams

Confirm the plan (Free, Pro, Business+ or Enterprise) and write it in your application inventory. It decides which export you can run (see the table in Step 2).

On Pro, Business+ and Enterprise, the Channels tab shows each channel's activity, last use and member count. Select Export CSV and use it to choose which channels to migrate. Many quiet channels are better archived than moved. The Free plan shows only the Overview tab.

Review the installed apps and how many configurations each has. For each one, write down what it does for the channel, because that outcome is what you rebuild in Teams. Record the result in your Application inventory and dependency map.

Export the member list with emails and account types (full member, single-channel guest, multi-channel guest). Every Slack user, including deactivated users, must map to a Microsoft 365 account or to Unknown user before the tool will migrate. Copy the list into your Identity and licence mapping sheet.

Microsoft's tool does not migrate archived channels. Do this before you export. Select each archived channel you want to keep, click the channel name in the conversation header, then Settings > Unarchive this channel.

Choose an option under Export date range and select Start Export. On Business+, use the "submit an application" link on the same tab for a full export including private channels. On Enterprise, Org Owners, Org Admins and members with the Export Admin role can export. When Slack emails you, open "Visit your workspace's export page" and select Ready for download to get the ZIP.

The ZIP holds your organisation's message history. Store it only in the migration storage account and delete it when the migration is finished. Delete the local copy once it is uploaded.

A Global Administrator grants one-time consent for the M365 Teams Migration app: open the consent link from Microsoft's introduction page and, at Permissions requested, select Accept. Microsoft recommends running the migration as a Microsoft 365 Migration Administrator. SharePoint Administrator or Global Administrator also work.

On Basics pick the subscription and resource group, a unique name, a region (Microsoft recommends East US or West US 2 outside Europe, North Europe or West Europe in Europe), Standard performance and LRS. On Advanced set Enable storage account key access to Disabled, Allow enabling anonymous access on individual containers to Disabled and Minimum TLS version to 1.2. On Data protection enable soft delete for blobs and containers. Select Review + create, then Create. The Azure CLI commands below do the same in Bash.

# Sign in and create a storage account for the Slack export (names are examples)
az login
az group create --name rg-slack-migration --location eastus
az storage account create --name contososlackexport --resource-group rg-slack-migration --location eastus --sku Standard_LRS --https-only true --min-tls-version TLS1_2 --allow-shared-key-access false

# Give the migration service read access to blobs
SP_ID=$(az ad sp list --display-name "Office 365 Mover" --query "[0].id" -o tsv)
SA_ID=$(az storage account show --name contososlackexport --resource-group rg-slack-migration --query id -o tsv)
az role assignment create --assignee-object-id "$SP_ID" --assignee-principal-type ServicePrincipal --role "Storage Blob Data Reader" --scope "$SA_ID"

# Create a container, upload the export and print its URL
# (your own account needs a data role such as Storage Blob Data Contributor to upload with --auth-mode login)
az storage container create --name slackexport --account-name contososlackexport --auth-mode login
az storage blob upload --account-name contososlackexport --container-name slackexport --name slack-export.zip --file ./slack-export.zip --auth-mode login
az storage blob url --account-name contososlackexport --container-name slackexport --name slack-export.zip --auth-mode login -o tsv

Select Storage Blob Data Reader, then Next. Keep User, group, or service principal, select + Select members, search for Office 365 Mover, select it and select Select, then Next and Review + assign. You need User Access Administrator to do this.

Select Add container, enter a name and select Create. Open the container, select Upload > Browse for files, pick the Slack ZIP and select Upload. Select the uploaded file and copy the URL from its Overview tab.

Paste the blob URL into Export file URL in Azure Blob Storage, select Upload file and then Complete setup. For Enterprise exports, choose the workspaces in Select workspaces for scan and migration and select Save.

Tick channels, select Scan messages, and wait for Channel scan status to show Completed. Review the message counts and last message dates. Then tick the channels to move and select Send to migration, choosing Send all messages to migration or Only send messages from the selected date range (UTC, applied to root messages; replies follow their root).

This script checks which Slack members in the export's users.json have a matching Microsoft 365 account, so you can fix gaps before mapping.

# Optional pre-check: which Slack members have a matching Microsoft 365 account?
# Run from the folder where you unzipped the Slack export.
Connect-MgGraph -Scopes 'User.Read.All'
$slackUsers = Get-Content -Raw -Path .\users.json | ConvertFrom-Json

$slackUsers | Where-Object { -not $_.is_bot -and $_.profile.email } | ForEach-Object {
    $email = $_.profile.email
    $safe  = $email -replace "'", "''"
    $match = Get-MgUser -Filter "mail eq '$safe' or userPrincipalName eq '$safe'" -Property Id,UserPrincipalName,AccountEnabled
    [pscustomobject]@{
        SlackId      = $_.id
        SlackName    = $_.real_name
        SlackEmail   = $email
        SlackDeleted = $_.deleted
        M365UPN      = ($match | Select-Object -First 1).UserPrincipalName
        Matched      = [bool]$match
    }
} | Export-Csv -Path .\slack-identity-check.csv -NoTypeInformation -Encoding UTF8

Select Auto-map (matches accounts with the same email address). Accounts still showing Mapping needed can be fixed one by one: select the row, type the user in Equivalent Microsoft 365 user or choose Unknown user, and select Save. For many users, select Export Identities, fill the Microsoft 365 Email ID (Enter unknown if user not present) column, then Import users > Select file and Save.

Choose Manually map to destination, then in Microsoft Teams name choose Create a new team or an existing team, and in Channel name choose Create a new channel and its type, then Add channel and Save changes. For many channels, choose Upload destinations and map, download MigrationDestination.csv, fill in team name, TeamID (or New), team type, channel name and channel type, and upload it. The tool can only migrate into channels it created. Microsoft recommends setting the destination channel type to shared. You cannot merge several Slack channels into one Teams channel.

A team supports up to 1,000 channels of any type, and deleted channels count for 30 days. Older Microsoft guidance quoting 200 channels per team is out of date. Count channels per team in the CSV before you upload it.

Migrate a handful of busy channels (tick them, Migrate, Start migration) and check threads, mentions, reactions, attachments and authors with the channel owners.

Tick the channels, choose Migrate in the toolbar, check the Before you migrate pane confirms identities are mapped and consent is granted, then select Start migration. Twenty channels run in parallel and the rest queue.

Microsoft prefers a single pass. If you need a second, upload a newer export from the same Slack workspace to Azure, provide it with Specify export file, then tick the earlier migration task and select Migrate > Start migration. Edits, deletions and new replies to already-migrated messages do not come across.

Tick the channels, select Generate report, wait, then open Recent actions and select the report link. Open SlackScanSummary.csv and SlackMigrationSummary.csv from the ZIP files.

Check whether each Slack app in your inventory has a Teams app in the Teams store. Many vendors publish both. Note which need admin approval in your organisation.

Office 365 Connectors in Teams, including connector-based incoming webhooks, were retired in May 2026. Search for the Send webhook alerts to a channel template (or build one with the When a Teams webhook request is received trigger), configure it and select Save. Copy the webhook link and point the sending system at the new URL. Use Adaptive Cards if you need interactive buttons.

Slack Workflow Builder flows do not migrate. Rebuild the ones still needed in Workflows or Power Automate, and have each owner test them.

In Slack a channel often works like a quick chat. In Teams, short back-and-forth belongs in chats and channels suit topic-based threaded posts. Show people where each kind of conversation goes and how to set notifications.

Pick a date when Slack becomes read-only for each group, so you do not chase deltas. Tell people that DMs are not moving and how long Slack stays available for reference.

Owners set up tabs, pin key files and model good habits. Give everyone else a one-page quick-start guide.

Select the Complete disconnect from Slack Import button at the top of the page, then Delete in the Delete data to complete disconnect dialog. Download the reports first.

Delete the blob container and export file, or the storage account. In the Microsoft Entra admin center find the M365 Teams Migration app under Enterprise apps and revoke its permissions or delete it.

az storage account delete --name contososlackexport --resource-group rg-slack-migration --yes

Keep Slack for as long as your retention policy needs, export anything you must keep, then downgrade or close the workspace.