Background: There are a number of pathways available for international students to gain admission into universities in English-speaking countries. While many international students for whom English is not their first language succeed academically, there is concern that some do not cope with the demands of university which can affect their retention and academic success. This study considers the effects of different admissions pathways on international undergraduate students' academic success in one New Zealand university. Purpose: Findings from the first phase of this research revealed that international students who entered university with the National Certificate of Educational Achievement (NCEA) gained at high school in New Zealand performed significantly worse academically than their peers who entered through three other admissions pathways. This study aimed to ascertain whether there were salient features of students' prior education and undergraduate experiences which contributed to this outcome. Method: In-depth interviews were conducted with nine students who entered a university in New Zealand via two admissions pathways: NCEA or the International English Language Testing System (IELTS). The data generated through these interviews was analysed to enable qualitative comparisons between the two groups. Findings: Results suggest that the IELTS group outperformed their NCEA peers due to maturity and prior education in their home countries. While the NCEA students had spent some years at high school in the host country, they did not, in general, demonstrate the same level of academic literacy as their IELTS peers. Conclusion: International students' outcomes appear to differ due to previous educational experiences. Students who enter via NCEA are potentially more likely to need support, as they may still be dealing with language proficiency issues, whereas those who enter via IELTS with prior higher-level education in their home country may be more academically prepared. It is important that institutions promote learning support opportunities for all international students, to ensure they experience a positive social and learning experience, which can ultimately contribute to their retention in learning, and their academic success.