If you don't have uBO installed, and wish to install on a pre-Catalina version of Safari, Download the latest (and final) release here and follow these instructions to install it.

Anybody with uBO currently installed, it won't be removed until you update to Safari 13.

For the moment continue to use Safari 12 with uBlockOrigin.

If you are a current user of uBlock Origin for Safari here are the options to continue blocking ads: It will not possible for uBlock Origin to work with the upcoming Safari 13 / macOS Catalina release Though it is still curently possible to install uBlock Origin by downloading the extension from Github (edit: must follow these instructions, it will not be starting from Safari 13 / macOS Catalina, when the legacy entension API will be fully deprecated. Safari also recently shut their Extension Gallery, instead redirecting it to the mac app store.

From Safari 12 / macOS Mojave, old legacy Safari extensions were still allowed, but came with warnings saying that they will slow down your browsing (they infact won't, or at least not noticably). Since then Apple has begun phasing out Safari extensions as extensions, and has instead been implenting a new extensions framework which is extremley limited in adblocking functions, only allowing 'content blockers', which are just links bundled as an app which Safari enforces. UBlock Origin was ported for Safari in 2016, and was updated regulary (mostly changes from the main project) until 2018 when development completley stopped. This should answer all questions on the status of uBO for safari. In the past few months, and especially in the past week, there have been a lot of posts and comments questioning the status of uBlock Origin for Safari. Very quick tl dr: uBO will no longer work with Safari, use Firefox or a new 'content blocker' app (see below for good replacements).

Origin app store