The Beijing Olympic double gold medallist called time on her career just days before her 24th birthday, saying she felt too old to keep up with the new generation of talent.
And the Mansfield swimmer, who lost her 800 metres freestyle crown to 15-year-old American Katie Ledecky at last year's London Olympics, says there is no chance of her making a shock u-turn and returning to the pool.
Instead, she is happy focusing on promoting swimming in the UK and preparing for the next major step in her life - marriage to swimmer Harry Needs.
We caught up with her and heard about the sense of normality that she has discovered since hanging up her swimming cap, her work in primary schools, plans for the future and favourite British Olympians of all time.
You announced your retirement at the beginning of February. Any regrets?
Definitely no regrets. It was the right time. I had an amazing journey and loved every second but it felt the right time to stop.
Swimming usually means hours of early morning training. How do you spend the time now?
Asleep! It’s nice, I get to wake up when it's light outside.
You said you were too old for swimming so what has the transition been like to the normal world where you are still a young woman?
I definitely feel a lot younger in the normal world. Having said that I’ve just got engaged which makes me feel grown up. It’s nice as I’m not putting my body through anywhere near the stress and hard work I was when I was training. It’s nice to feel a bit more normal.
The Olympic Games have shown that swimming is now a sport for teenagers. Katie Ledecky, Ruta Meylutite and the Chinese Shiwen Ye were all Olympic champions aged under 16. Do you think it is good for a swimmer to reach the height of her career so young and did you consider Ledecky a potential gold medallist before the 800m final in London?
I think women's swimming has always been younger than men's swimming. I think it’s a very young sport even before the Olympics. Especially for longer distance races, where the training is brutal and your body can handle it better when you're younger. I know Katie swam fast at her trials. I considered everyone in that race a potential winner and it was anyone's for the taking. Katie went out for it and swam an incredible race.
You won two golds in Beijing and two bronzes in London. What medal do you consider the most important?
I think they are all important for many different reasons. My favourite, I would have to say, was the 800 in Beijing as my parents were there and breaking the world record was just such a shock.
You said that your goal now is for every primary school child to be able to swim 25m. How can you achieve that?
I think it can be achieved with the right programme and making it more fun, the way swimming should be done. I hope I can encourage, inspire and hopefully give people the knowledge on swimming that they need. My learn-to-swim program is called Becky Adlington's Swim Stars and I intend to do just that with my programme throughout the UK and hopefully Europe.
Your ex-coach, Bill Furniss, has been nominated head coach of the British National Team. Have you considered following him and becoming a coach?
I wouldn’t become a coach. I couldn't handle the early mornings. I definitely prefer teaching to coaching.
Has swimming become more popular since your achievements?
I would like to believe so. I don’t know figures or if that is true though. I definitely think the profile has raised and people are a lot more interested and know more about it.
You were the first British swimmer who win a gold medal since 1988 and the first to win two golds at one Games since 1908. How long do you predict before that feat is matched?
I think anything is possible if you believe it and work hard enough for it so I wouldn't like to put a time or a year on it!
Is true that you are a Derby County supporter? Do you like football or is your interest purely down to your great uncle having been a pro?
My dad's uncle played for Derby County, he was a goalkeeper. My dad took me to their games when I was growing up. He is still a season ticket holder now.
If you were to make a list of the best British athletes of recent years who would you choose?
That is hard. Not in any particular order but Chris Hoy, Mo Farah, Bradley Wiggins, Ellie Simmonds.
Would you consider returning for the Commonwealth Games in 2014, with this year as a sabbatical?
Definitely not. You wouldn’t be able to do that in swimming. The feel for the water is so important, especially for distance swimming. I would have to give it 100 per cent or nothing. I’m a very proud ambassador for Glasgow 2014 and I will be there cheering but not competing.
Many other swimmers have retired only to return to action. Do you see any possibility of this?
I don’t think so. I know I've had my time competing at the top and with the best. Not many people come back and perform better or just as good as before. I don’t feel like I have any unfinished business or the desire to make a comeback.
Will you go to watch the Swimming World Championship in Barcelona this summer?
I would like to think so yes if possible.
Have you ever thought of entering politics to pursue your project of spreading the word about swimming in schools?
Not really. I’m very passionate about school swimming but wouldn't want to get to ahead of myself. I would need to learn and educate myself on it a lot more before I even considered that.
You have announced that you are now engaged. How does that feel?
Very happy. I’m extremely lucky.