Why 'quiet quit' when you can 'quiet vacation'? Millennials are taking time off without telling their bosses. Gen Z has a different tactic.

Nearly four in 10 millennials said they have taken time off without telling their boss, a poll found. Just 24% of Gen Zers and Gen Xers said the same.

• Millennials are "quiet vacationing" or taking time off without informing their employers.
• A Harris Poll found that 38% of millennials have taken secret time off, more than Gen Zers and Gen Xers.
• Many workers face pressure to be always available, which may be blurring lines between work and PTO.

Quiet quitting — coasting along at your job without actually leaving it or giving up your salary — became all the rage in the early years of the remote work era, but some workers have found another way to take a break from their jobs.

Rather than coast along indefinitely, some employees are opting to take time off without formally taking any paid time off, let alone informing their bosses.

It's called "quiet vacationing," and millennials, in particular, seem to love it.

Nearly four out of 10 millennials said they've taken time off work without actually informing their employer, according to a new survey of 1,170 employed Americans conducted by The Harris Poll. That's compared to 24% of Gen Zers and Gen Xers who reported doing the same. The survey was conducted online between April 26 and 28.

Millennials were also more likely to say they have taken actions to make it appear like they are working when they really aren't: 38% of millennials said they've moved their mouse just to keep their status on messaging apps active compared to 30% of Gen Zers.

They even want to look like they're working when they're supposed to be off the clock, with 37% of millennials saying they've purposefully scheduled a message to send outside their usual hours to make it look like they're working overtime. Only 27% of Gen Zers said they've done the same.

"There's a giant workaround culture at play," Libby Rodney, The Harris Poll's chief strategy officer, told CNBC, adding, "It's not exactly quiet quitting, but more like quiet vacationing."

Millennials may be quiet vacationing more than other groups due to generational differences. Rodney told CNBC that Gen Z is more vocal about criticizing employers that don't have a good work-life balance, while millennials are more likely to find a quiet workaround "behind the scenes."

The Harris Poll also found that 78% of American workers reported not using all their PTO days, with nearly as many saying they wish they were able to take all of their available days off.

About a third of respondents said the biggest barriers to them taking more PTO was pressure to always be available and meet work demands, as well as a heavy workload.

More than half of employees said they had taken work-related calls while on vacation, while 86% said they'd check an email from their boss while on PTO, suggesting that work time and personal time may be bleeding into each other in both directions.

Have you taken time off without telling your employer? Have a news tip or story to share? Contact this reporter at kvlamis@businessinsider.com or through secure-messaging app Signal at 708-476-8802.