This list only includes independent, fully free and open source Linux distributions that are primarily designed to run on mobile devices.  Distributions are listed in alphabetical order.

Name Focus Supported devices Based on Android apps
AsteroidOS Wearables 8 OpenEmbedded no
LuneOS Smartphones, Tablets, SBCs 11 HP WebOS no
Maemo Leste Smartphones, SBCs 11 Maemo/Devuan no
postmarketOS Phones, tablets, wearables 130+ Alpine Linux WIP
SHR Smartphones 4 OpenEmbedded no
Ubuntu Touch (UBports) Phones 14 Ubuntu LTS possible (anbox)

Other mobile Linux distributions

Those distributions are not included in the list above for several reasons, but still available for reference.

Name Reason
Android/LineageOS/... Clearly not "an Android alternative" for older devices
KaiOS UI is not open source, only for a limited number of non-touch devices
Manjaro Phone Only announced, for now
PureOS Exclusively for Purism devices
Sailfish OS Not fully open source, not independent
Tizen Not independent, not fully open source, only for Samsung devices