Lack of access to safe abortions continues to be a major sexual and reproductive health concern. Adolescents can face barriers to safe abortions due to the unique implications of their age. Understanding adolescent abortion experiences and care trajectories is critical. Qualitative and quantitative evidence is analysed from interviews with 313 adolescents aged 10-19 years who sought abortion-related care in public health facilities in Addis Ababa (Ethiopia), Lilongwe (Malawi), and Lusaka (Zambia) between April 2018 and September 2019. The trajectories framework is used to understand how adolescent abortion-related care-seeking differs across a range of socio-legal national contexts. A comparative study design incorporates varying levels of restriction on access to abortion: Ethiopia (legal on broad social or economic grounds, services implemented); Zambia (legal on broad social or economic grounds, complex services with barriers to implementation and information provision); and Malawi (legally highly restricted). Most adolescents (n = 97, 98%) in Ethiopia obtained a medically safe abortion, and most adolescents (n = 70, 64%) in Zambia and almost all adolescents (n = 94, 94%) in Malawi obtained a less medically safe abortion. There is a significant association between country and whether an adolescent tried to end a pregnancy before coming to the facility, X²(2, N = 313) = 135.93, p < 0.001. In Malawi 97% (n = 101) of adolescents had sought to end the pregnancy before coming to the facility, compared to 18% (n = 18) in Ethiopia. Cross-country variations in the relative safety of the abortion and type of care sought by adolescents reflect national laws, policies and service availability. The most facility-based abortions were recorded where care is most accessible (Ethiopia), and most non-facility-based and least safe abortions were recorded where care is the most restricted (Malawi). Across all countries, adolescents experienced delays to their care-seeking; 39% (n = 39), 71% (n = 74), and 66% (n = 73) in Ethiopia, Malawi, and Zambia respectively. Adolescents reported high levels of respectful treatment across countries, with a minority reporting negative experiences. A minority of adolescents in each country reported that unofficial money was paid to facility staff. There were different experiences of post-abortion contraception in the three countries, including an absence of choice. Adolescents' trajectories - particularly those involving multiple attempts and barriers to achieving abortion care - require tenacity and determination. Our analyses show that less restrictive abortion policies and accessible abortion services improve adolescent chances to access abortion care.