To import PST files to Thunderbird, utilize the RecoveryTools PST to Thunderbird Converter. This tool allows you to seamlessly convert PST files to Thunderbird-compatible formats, such as MBOX, EML, or EMLX. Simply select the PST file, choose the desired output format, and the Converter will efficiently convert and import the data into Thunderbird, preserving all email content, folders, and attachments.