Get ready, get set, say cheese!

Being Taylor Swift's friend comes with two rules - be prepared to travel at a moment's notice and be ready to pose for Instagram pictures while doing so.

The Haim sisters - Este, Danielle and Alana - are certainly realising this the fun way after joining the pop star on holiday in Hawaii on Friday.

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Girly vacay: Taylor Swift and sisters (L-R) Alana, Este and Danielle Haim landed in Maui, Hawaii, on Friday

The musical pack - the sisters form band Haim - were indulging in some girly vacation time on the high seas after jetting off to the tropical state.

The 25-year-old and the Los Angeles alt band have become fast friends since playing the Jingle Ball together over the holidays.

Making sure to keep all their fans in the loop, the Shake It Off star posted plenty of pictures of her and her friends cavorting in their bikinis while on the hunt for whales.

Bikini party: The 25-year-old singer enlisted Este for some piggy back fun in the tropical waters

Cool cardio: Posing next to a rocky stream, the pop star captioned the image, 'Hiking with the Squad in Hawaii'

Kicking off her newest social media pictorial, Taylor posted a snap of her and the girl band standing aboard their yacht with the blue waters of Maui behind them.

Looking like a swimsuit advert, each of the musicians wore a different type of bikini.

Taylor started off her day in a pink and citrus striped halter bra bikini complete with frills.

In contrast, Alana wore a retro-inspired black and white high waisted two piece while sister Este wore a floral swimsuit and Danielle went for a classic bandeau black bikini.

While first the ladies soaked in some sun aboard their yacht they did not just laze around all day, as Taylor's next holiday snapped showed.

The foursome headed to shore to work up an appetite before lunch by going for a hike.

Posing next to a rocky stream, the pop star captioned the image: 'Hiking with the Squad in Hawaii.'

Enjoying being on land, the ladies then went for a dip off the beach - which also say Taylor make her second swimsuit change of the day.

Strike a pose: The group were on a mission to see whales, but still found time to snap pictures that made them look like a swimwear commercial

Taking inspiration for Alana's retro look, the Blank Space singer donned a black with white spot 1950s one piece.

Clearly loving her pin up look, Taylor posed up on the sand while enlisting on of the other girls to take pictures of her.

Not afraid to have a little laugh at herself, the singer captioned the image with a reference to a Saturday Night Live skit about her, saying 'She's always wearing, like, a 1950's bathing suit'.

But the group was not done there, as their afternoon was spent whale watching - much to Taylor's delight.

Quick change: First wearing a bright bikini, the Blank Space singer then donned a black with white spot 1950s one piece

The 25-year-old made a video of one whale that came close to their boat.

Trying to alert the other girls, the star can be heard yelling in the background.

'Whale, Whale. Look at it! Yes, whale.'

Taylor's little trip away comes on the same day it was revealed that she will be making a big trip soon - to England.

The singer will be performing at the annual BBC Radio 1's Big Weekend music festival held this year on May 23 and 24 in Norwich.