It’s hard to keep up with how quickly Kim Kardashian and Khloe Kardashian‘s daughters are growing up.

In a new Instagram photo shared by the SKIMS founder, Kim and Khloe’s 𝘤𝘩𝘪𝘭𝘥ren appear to enjoy a spring break by the beach, and in one photo, the Kardashian sisters’ daughters, True and North, are practically teenagers.

The first pic in Kim’s April 8 Instagram post, aptly captioned, “spring break,” shows North, 10, posing with True, who will turn 6 April 12, on her back. The eldest Kardashian-West is donning a simple gray T-shirt with her hair in two half-pigtails. Meanwhile, True wears a white floral tank top with her hair in partially purple braids.

It appears the family celebrated True’s upcoming 𝐛𝐢𝐫𝐭𝐡day during their time off, as the last slide of Kim’s post includes a pink balloon sign reading, “Happy Birthday True.” Other highlights include a sightseeing boat ride to see dolphins and time at the beach.Kim’s other 𝘤𝘩𝘪𝘭𝘥ren Saint, 8, Chicago, 6, and Psalm, 4—whom the 43-year-old shares with former husband Kanye West—as well as Khloe and Tristan Thompson‘s son Tatum, 20 months—joined in on the trip. (While Tatum wasn’t included in Kim’s post, he was featured in one of Khloe’s posts from April 6.)

And Kim and Khloe’s eldest 𝘤𝘩𝘪𝘭𝘥ren not only look grown up—they’re also coming into their own. After all, North has leapt into a music career with a feature on her father’s latest disc Vultures, and even teased her own album, Elementary School Dropout, during one of Kanye’s listening parties for the Vultures 2 record back in March.

As she told the crowd at a March 10 show in Phoenix, Arizona, “I’ve been working on an album.”

Meanwhile, Khloe also shared another grown-up update of True, Chicago, and brother Rob Kardashian‘s daughter Dream celebrating Easter together on April 1.

Read on for more sweet moments from the Kardashians’ kids.