Travelling outside of Ireland into Europe also depends on the passport you hold, but since you had to obtain a visa for Ireland, I would assume you need a visa for the UK and other European countries and since it's a single entry visa I wouldn't risk leaving the Republic. From personal experience I wouldn't be so confident about going over the border into N. Ireland without travel documents. I tried it in 2004, when there were "No border controls" and as we got to the border 2 immigration officials bordered the bus and I had no documents on me, thankfully I was able to sweet talk my way out of it and not get deported.

Stay in Ireland and explore the beautiful country!

Travelling outside of Ireland into Europe also depends on the passport you hold, but since you had to obtain a visa for Ireland, I would assume you need a visa for the UK and other European countries and since it's a single-entry visa I wouldn't risk leaving the Republic. From personal experience I wouldn't be so confident about going over the border into N. Ireland without travel documents. I tried it in 2004, when there were "no border controls" and as we got to the border 2 immigration officials boarded the bus and I had no documents on me, thankfully I was able to sweet talk my way out of it and not get deported.

Stay in Ireland and explore the beautiful country!