To avoid his yacht being seized Russian oligarch sailed at full speed for 18 days.

[BumRushDaShow]

13. But look who is "nearby" to Fiji

But yes, Australia has its own sanctions - https://www.dfat.gov.au/international-relations/security/sanctions/sanctions-regimes/russia-sanctions-regime

But since the country is so huge, I suppose the yacht pilot figured they could make a beeline for some obscure location along the Australian coast and try to "blend in" through some arrangement with someone there. I expect Australia may try to find out who was arranging that.