https://www.citizensinformation.ie/en/moving_country/moving_to_ireland/coming_to_live_in_ireland/visa_requirements_for_entering_ireland.html#:~:text=Ghana-,Visa%20waivers%20for%20UK%20visa%20holders,for%20a%20separate%20Irish%20visa.

Visa waivers for UK visa holders
The Short Stay Visa Waiver Programme allows nationals of a number of Eastern European, Middle Eastern and Asian countries who have a short-term UK visa, to come to Ireland without the need for a separate Irish visa. The countries included in the scheme are:

Bahrain
Belarus
Bosnia and Herzegovina
China
Colombia
India
Indonesia
Kazakhstan
Kosovo
Kuwait
Montenegro
North Macedonia
Oman
Peru
Philippines
Qatar
Russia
Saudi Arabia
Serbia
Thailand
Turkey
Ukraine
Uzbekistan
Vietnam

Citizens of India and China, who have a short stay UK visa can travel to Ireland under the British Irish Visa Scheme (BIVS) without a separate Irish visa. You can also use your Irish visa to travel to the UK. Your visa must be endorsed with ‘BIVS’.


https://www.irishimmigration.ie/coming-to-visit-ireland/frequently-asked-questions/

The Short-Stay Visa Waiver Programme allows nationals of certain countries, who have entered the UK on foot of a UK short stay visa, to travel to Ireland without the requirement to obtain an Irish visa. They instead may use the time remaining on their current leave to remain in the UK.

In order to avail of the Programme you must have landed and gained lawful entry to the UK on foot of your current UK visa, prior to undertaking the journey to Ireland.