Almost nine out of every ten adults in Ireland now has access to a smartphone.
A new survey has also found that nearly three quarters of those aged 18-24 check their phone in the middle of the night.
The research was carried out by Ipsos MORI on behalf of Deloitte among a nationally representative sample of 1,000 Irish adults.
It found more people in Ireland have access to smartphones than laptops or tablets.
87% of those aged 18-24 use their devices "always" or "very often" when using public transport, meeting friends, shopping or watching TV.
Over a third said they reach for their smartphone within five minutes of waking up, with messages the first thing to be checked, followed by social networks and personal emails.
16% of those aged 25-34 said they have arguments once or several times a week with their partners over mobile phone usage.
App usage is particularly high among Irish consumers, with a fifth of respondents saying they have 11 to 20 on their smartphone.
Two fifths take photos daily on their device, while 57% regularly use their phones to watch short videos.
Smartphone owners in Ireland also like online shopping, with 43% using their phones for viewing shopping website at least once a week.
