Both .db3 and .sqlite files are databases, so it is likely that their data can be somehow exported or transferred from one database management program to another. Below is a list of such programs know to support both of these file types and thus possibly capable of DB3 to SQLITE conversion.
Convert Database file to SQLite database.
We found 7 software records in the database related to .db3 to .sqlite file format conversion.
Microsoft Windows software - convert db3 to sqlite on Windows
A software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine
Convert from db3 file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned db3 to sqlite. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A database administration tool for SQLite databases
Apple macOS / Mac OS X software - convert db3 to sqlite on OS X
Transactional SQL database engine for Apple Mac computers
Mac version of the database administration tool for SQLite
Linux/Unix software - convert db3 to sqlite on Linux
A database engine in version for Linux
A linux version of the database administration tool for SQLite
Multiplatform software - convert db3 to sqlite on any platform
SQLite database manager