How to Import PST to Fastmail in Bulk?

Sarabjeet Kaur | outlook pst software technology | 6 minutes read | Modified on: 22-01-2026

If you are searching for a perfect and simple method to import PST to Fastmail with email attachments, then this segment will help you complete the process smoothly. In this article, we’ll explain both a practical manual approach and an expert solution to import Outlook emails to Fastmail. By the end of this write-up, you’ll be able to export your data easily while maintaining complete data integrity and avoiding any data loss.

Fastmail is a generally used email service across the globe and is especially known for its strong safety features. It provides both free and paid account options to meet different user needs. A lot of users choose Fastmail when switching their email platform due to its efficient email management capabilities. Fastmail can be accessed from anywhere with a stable internet connection, making it very convenient. In contrast, PST files can only be accessed through supported email clients, which creates limitations.

This brings up an important question: Is it possible to open PST files in Fastmail? In the following section, we’ll address this query and explain the available solutions in detail.

Can Outlook PST Files Be Directly Imported into Fastmail?

No, Fastmail doesn’t offer a native option to import PST files directly. PST files are designed specifically for Microsoft Outlook, so they are not compatible with Fastmail. To import Outlook emails into Fastmail, you must first convert the PST file into a supported format like MBOX or EML, or transfer the emails using the IMAP method. This helps ensure a smooth migration of emails along with their attachments.

Reasons to Import PST to Fastmail

Fastmail offers strong privacy and security features to protect your email data more effectively.
Fastmail provides advanced tools like powerful search, filters, and folders for better organization.
Importing PST to Fastmail removes the need for Microsoft Outlook to access old emails.
Storing PST data in Fastmail helps prevent data loss caused by local system failures or corruption.

How to Import PST to Fastmail Email? – Using Manual Way

1. Add PST File into Microsoft Outlook

First, open the MS Outlook app on your system.
From the top navigation menu, click on the File tab.
Now pick the Open & Export option from the list.
Next, click on the Import/Export button.
Opt Import from another program or file and tick Next.
Choose Outlook Data File (.pst) and proceed further.
Browse and pick the PST file saved on your local machine.
Finally, click on the Finish button to complete the process.
Once imported, drag and drop the PST file into your primary Outlook mailbox.

Now, proceed to the next step.

2. Convert PST to MBOX Using Thunderbird

To move PST data to Fastmail, you must first convert PST into MBOX format.
Download and install the Mozilla Thunderbird email client.
Launch the application on your computer.
Configure any email account within Thunderbird.
Go to the top menu and click on the Tools option.
Select the Import option from the menu.
Click on the Continue button.
Choose the folders you want to import based on your requirements.
Again, click Continue to proceed.
On the final screen, click Start Import.
Thunderbird will now automatically import all Outlook data.
Your emails will be stored in separate folders within Thunderbird.

Let’s move to the next step.

3. Install ImportExportTools NG Add-on

Open Thunderbird and click on the gear icon to access settings.
Navigate to Add-ons and Themes.
Search for ImportExportTools NG extension.
Click on the extension and select Add to Thunderbird.
The add-on installation process will complete successfully.

Now continue to the next step.

4. Export Emails as MBOX File

Open the folder created during Step 2.
Right-click on the selected folder.
From the options, select ImportExportTools NG.
Click on Folder Export.
Choose the option Export as MBOX file.
Pick a destination path to store the MBOX file.
Done! Your MBOX file is now successfully created.

Proceed to the final step.

5. Upload MBOX File into Fastmail Account

Open any web browser and log in to your Fastmail account.
After logging in, click on the gear icon in the dashboard.
Navigate to the Migration section.
Select the Upload MBOX file option.
Click on the Upload File button and select the MBOX file created earlier.
Wait for a few minutes while Fastmail uploads your data.
Once completed, your emails will appear in your Fastmail account.

By following these steps carefully, you can successfully import PST to Fastmail.

Drawbacks of the Manual PST to Fastmail Method

Before proceeding further, it is important to understand the limitations of the above manual approach:

High chances of data integrity loss
The process is lengthy and time-consuming
Multiple steps may confuse non-technical users
Requires strong technical knowledge
Any minor mistake can cause permanent data loss
Email attachments may not be imported correctly
Not suitable for large PST files or bulk migration
Manual methods may fail in certain scenarios

These are the major limitations of using the manual solution to import PST into Fastmail. If this method does not work for you, then you can move on to the alternative solution discussed next.

How to Import PST to Fastmail in Bulk? – Using an Expert & Powerful Software

If the manual method does not work properly or fails to deliver the expected results, you can choose a professional solution like the BitData Migration PST Converter to import PST files into Fastmail easily. This advanced tool is designed with a user-friendly interface that allows direct PST to Fastmail migration while maintaining complete data integrity. It enables you to transfer entire mailbox data, including emails, attachments, folders, and metadata, without requiring Microsoft Outlook.

Windows
Mac

The PST to Fastmail Converter supports batch migration, making it possible to import multiple Outlook files into Fastmail account at the same time. Moreover, it preserves the original folder structure and email formatting throughout the process. Even non-technical users can perform the migration effortlessly by simply adding the PST file, entering FastMail login credentials, and starting the transfer. You can also download the demo version of the tool to evaluate its functionality, which allows importing up to 25 emails per folder for testing purposes.

Steps to Import Outlook PST Emails into Fastmail Email

Download and open the PST to Fastmail Migration Tool on your device.
Click on Add Files or Add Folders to load the PST files you want to import into Fastmail.
Preview the loaded PST data and click Next to continue.
From the list of available saving options, select IMAP as the destination format.
Provide your Fastmail email address, password, and IMAP host details correctly.
Click on the Convert button to begin importing PST data into your FastMail account.

Why Choose an Expert-Recommended Outlook Converter for Importing PST to Fastmail?

There are several reasons why experts suggest using a professional Outlook to Fastmail Migration Tool to import Outlook to Fastmail. Some of the key advantages are listed below:

Allows direct import of PST data into a Fastmail account without manual steps.
Supports IMAP migration to transfer complete mailbox data, including emails and attachments.
Maintains original folder hierarchy, email formatting, and metadata during the process.
Ensures complete security of Fastmail login credentials throughout the migration.
Enables batch conversion to import multiple PST files into FastMail simultaneously.
Works without requiring Microsoft Outlook installation.
Compatible with both Windows and Mac OS, supporting all major versions.

Last Verdict

In this segment, we explained that importing Outlook PST emails into Fastmail can be done using two different approaches. The manual method is lengthy, time-consuming, and requires strong technical expertise, making it less suitable for many users. On the other hand, the recommended professional tool simplifies the entire process and allows you to import PST files into Fastmail effortlessly. This utility saves valuable time and ensures that all emails, attachments, and mailbox data are transferred with complete data integrity in just a few clicks.

If you are looking for an instant and hassle-free solution, you can try the trial version of the suggested tool to evaluate its performance. Once you are satisfied with the results, you can upgrade to the licensed version for full and unlimited migration.