There is no direct way to Import MBOX to Outlook 2013. So in this case choosing a professional tool to convert MBOX to PST is a crucial decision. But feel free here I am suggesting a powerful tool that definitely will help you.

MailsDaddy MBOX to PST Converter to import MBOX to Outlook

MailsDaddy MBOX to PST Converter export single or multiple MBOX files to Outlook instantly. The application generates a preview of email messages and attachments to read and analyze before export. Users can filter and select important email messages using several filter options. This MBOX converter saves MBOX file to PST, MSG, RTF, EML, HTML, and other formats. It provides an option to create a single PST or separate PST file for mailboxes. With the help of this tool, direct import MBOX to Office 365 and Live Exchange Server is also possible. A free MBOX converter version of it is also available that supports up to 20 items per folder.
Use MBOX to PST Conversion Software and transfer effortlessly from MBOX email clients to Outlook. The software allows migrating Thunderbird files to Outlook PST files. With Thunderbird emails to PST conversion, attachments are also exported by the tool. It preserves the email headers, formatting, and folder hierarchy of MBOX data items during the conversion. The Tool allows opening MBOX files into Outlook 2013, 2019, 2016, 2010, 2007, 2003, etc.
As a user, I always recommend a risk-free and smart explanation to convert MBOX into PST including email attachments and other mailbox items. MBOX to PST Converter Free is the most suggested and one of the finest explanations that easily convert and migrate MBOX files into PST, EML, EMLX, and MSG file formats. It sustains a particular folder hierarchy as it was before the conversion process and delivers the most precise results without any hassle. MBOX to PST Converter provides a selection to preview the emails before the migration procedure and enables the users to provide a custom folder name with the location of the ensuing file.