[8] Amanda has dual Norwegian nationality and was called up to Norway's under-19 team at one point.
[9][10] Amanda made her debut for the Iceland national team on 21 September 2021, coming on as a substitute for Gunnhildur Yrsa Jónsdóttir in the match against the Netherlands.
[11][12] On 11 June 2022, Amanda was called up to the Iceland squad for the UEFA Women's Euro 2022.
[15] This helped Iceland win the Pinatar Cup for the first time in their history.
[16] Amanda's father Andri Sigþórsson was a professional footballer who represented Iceland at international level.