In terms of personality, Marine is rather dimwitted and so often acts before she thinks. She is relatively bossy and attention-seeking, and characters occasionally find her annoying. Also, due to her age and childish personality, she sometimes has trouble saying some words that Tails can say easily like "hovercraft" and "submarine".  She speaks with an exaggerated Australian accent, using Australian slang words such as 'strewth', 'bonza' and 'cobber' and adding the word 'mate' to the end of her sentences.

She is very afraid of ghosts and been so since very young. She is also very focused about proving herself and her image, and will often try act tough and in control in front of others even when she herself is skeptical or anxious, as she wants to prove her worth as a captain.