There is no Thunderbird app for iOS, but you can easily import contacts to Thunderbird using CopyTrans Contacts.
Here is how to sync iPhone contacts with Thunderbird Address Book in two steps:
Export iPhone contacts to a VCF file
The first thing to do if you want to sync iPhone contacts with Thunderbird Address Book is to prepare a VCF file with contacts from your iPhone. Here is how to do it:
First of all, download CopyTrans Contacts from the following page:
Export iPhone Contacts to Thunderbird
Install the program. If you need help installing CopyTrans Contacts, please refer to the installation guide.
Run CopyTrans Contacts and connect your iPhone to PC with a USB cable. Your iPhone contacts will appear in the main window.
After that, select the contacts you wish to export from the contact list, click on Export selected, then select Thunderbird (single .vcf file).To export all iPhone contacts to Thunderbird, tick the checkbox next to Contacts. To export a limited number of contacts, tick the checkbox next to each contact.
On your PC, navigate to the location where you want to place your iPhone contacts and click OK.If you are not sure where to export your iPhone contacts to, simply put them on your Desktop.
Your contacts will now be exported to a single vCard file in the folder of your choice.
CopyTrans Contacts features:
Thunderbird import contacts
Now it’s time to import your address book to Thunderbird:
Run Thunderbird and navigate to Tools > Import.
Launch the wizard by selecting Address Books and clicking on Next.
Then, select the vCard file and click on Next.
Find the VCF file with your iPhone contacts and click on Open.
Finally, click on Finish and it’s done! Your contacts have been successfully imported to Mozilla Thunderbird Address Book.
You can see your imported contacts in Thunderbird by clicking on the Address Book button in the main program window.
Note: Thunderbird does not support importing contact photos and birthday dates.