I submitted my resume through a Canadian recruiter (cast-a-way), and was contacted for an initial skype interview about a month later. After that went well, I was invited to meet with the Carnival hiring team who happened to be hosting a group interview session in my city a couple weeks later.
It was a full day event, the morning started with an orientation about life on board and expectations, then we played games in front of the group to get a sense of our personalities and public speaking abilities, and finally we met one-on-one with Carnival representatives.
They asked us to bring with us a current resume, a copy of our passport, two letters of reference, background check, and any relevant degrees.
After I was told of my acceptance, I was required to complete a very thorough medical (physical, blood, urine) which cost me $500.
Once I was given the final go-ahead, someone from Carnival contacted me to help with onboarding.
Between submitting resume to first day on the job, six months.
Overall, the interview process was a very positive experience.