| Inns | HS |
| 333-5 | 90* | Ireland Under-19s v England Under-19s | Haslegrave Ground, Loughborough | 2023 |
| 291-9 | 65 | Ireland Under-19s v Australia Under-19s | MA Aziz Stadium, Chittagong | 2003/04 |
| 278-8 | 91 | Ireland Under-19s v West Indies Under-19s | Bert Sutcliffe Oval, Lincoln | 2017/18 |
| 267-9 | 82 | Ireland Under-19s v New Zealand Under-19s | Mangaung Oval, Bloemfontein | 2023/24 |
| 265-9 | 51 | Ireland Under-19s v Canada Under-19s | MA Aziz Stadium, Chittagong | 2003/04 |
| 265 | 81 | Ireland Under-19s v Zimbabwe Under-19s | Absa Puk Oval, Potchefstroom | 2023/24 |
| 259-9 | 95 | Ireland Under-19s v West Indies Under-19s | Khulna Divisional Stadium, Khulna | 2003/04 |
| 248 | 65 | Ireland Under-19s v Zimbabwe Under-19s | Harare Sports Club, Harare | 2024/25 |
| 241-6 | 88 | Ireland Under-19s v Zimbabwe Under-19s | Harare Sports Club, Harare | 2024/25 |
| 236-7 | 75 | Ireland Under-19s v Bermuda Under-19s | Johor Cricket Academy Oval, Johor | 2007/08 |
| 236 | 69 | Ireland Under-19s v Zimbabwe Under-19s | Harare Sports Club, Harare | 2024/25 |
| 235-7 | 69 | Ireland Under-19s v Scotland Under-19s | Sheikh Kamal International Cricket Stadium, Cox's Bazar | 2015/16 |
| 235-8 | 90 | Ireland Under-19s v Bangladesh Under-19s | Mangaung Oval, Bloemfontein | 2023/24 |
| 235 | 90 | Ireland Under-19s v Zimbabwe Under-19s | Harare Sports Club, Harare | 2024/25 |
| 225-8 | 37* | Ireland Under-19s v Afghanistan Under-19s | Cobham Oval (New), Whangarei | 2017/18 |
| 216-6 | 66 | Ireland Under-19s v South Africa Under-19s | Queenstown Events Centre, Queenstown | 2009/10 |
| 212 | 37 | Ireland Under-19s v Papua New Guinea Under-19s | Khulna Divisional Stadium, Khulna | 2003/04 |
| 212 | 56 | Ireland Under-19s v New Zealand Under-19s | Khan Shaheb Osman Ali Stadium, Fatullah | 2015/16 |
| 210 | 69 | Ireland Under-19s v England Under-19s | Colombo Cricket Club Ground, Colombo | 2005/06 |
| 207-8 | 75 | Ireland Under-19s v Sri Lanka Under-19s | Cobham Oval (New), Whangarei | 2017/18 |
| 205-6 | 91* | Ireland Under-19s v Zimbabwe Under-19s | Harare Sports Club, Harare | 2024/25 |
| 204 | 31 | Ireland Under-19s v Zimbabwe Under-19s | Absa Puk Oval, Potchefstroom | 2023/24 |
| 201 | 70 | Ireland Under-19s v Bermuda Under-19s | Royal Selangor Club, Kuala Lumpur | 2007/08 |
| 196-8 | 53 | Ireland Under-19s v Zimbabwe Under-19s | Three Ws Oval, Cave Hill | 2021/22 |
| 191 | 47 | Ireland Under-19s v Kenya Under-19s | Gert Van Rensburg Stadium, Fochville | 1997/98 |
| 190 | 43 | Ireland Under-19s v England Under-19s | Haslegrave Ground, Loughborough | 2024 |
| 189 | 58 | Ireland Under-19s v India Under-19s | Shere Bangla National Stadium, Mirpur | 2015/16 |
| 186 | 94 | Ireland Under-19s v Zimbabwe Under-19s | St Catherine Club Ground, Bayfield | 2021/22 |
| 185-8 | 47 | Ireland Under-19s v Nepal Under-19s | Endeavour Park, Townsville | 2012 |
| 185-7 | 77* | Ireland Under-19s v South Africa Under-19s | Sheikh Kamal International Cricket Stadium, Cox's Bazar | 2015/16 |
