Does the entire trip fall during your BF's time? Or does BM have some of Friday and Monday? If ANY of the trip falls on BM's time, she is within her right to say "No." If the entire trip falls on your BF's time, then he is within his right to take SD out of school and go. 

This is the hard part about being the non-custodial or every other weekend household. Most of the time, skids won't be able to participate in family events or trips because they fall on the other parents time. Ideally, a healthy co-parenting BM would let it happen, bit if you're dealing with a HCBM, you're just setting yourself up for disappointment. 

It was in the CO. 

Until... we had an international trip that fell partially during school.  Since DW had full physical and legal, the visitation schedule was long distance and they only got time Summer, Winter, and Spring, we went. We never informed the SpermClan. Nor did we inform the court.  We just did it. None were the wiser. The SpermClan had declined that visitation so ... we used what would have been their time for our trip.

To avoid the drama of them pushing for extra days beyond the COd visitation schedule which clearly stipulated that SS could not miss school for visitation, we never allowed their visitation time to  cause him to miss school. They tried anyway. Even purposefly having him miss flights that were scheduled to get him home per the CO the day before school restarted. We always had SS collected by the police or sheriff from where ever the SpermClan was, and FIL got him to the airport on the same day but for a later flight.

This may be one of those things that you cannot make happen due to the CO. What does the visitation part of the CO stipulate?

It sounds that you are the NCP side of the equation. That makes these things more difficult to make happen.

You can write the letter to BM, but, as the CP, she can choose to not approve the request.  How likely is the BM in your blended family world to work with you on this?

Lesson learned. School schedules can change. You can ask, but now the decision is in BM's court.

As to whether it will be a school official excuse, that depends on the school. Here, as long as a parent submitted a written excuse it would be fine. But, in some places, the rules are different and vacations are considered unexcused absences (which depending on the district can have consequences).

IMHO.. kids shouldn't miss school for vacations.  The school will mark them as unexcused absences.  It isn't an "official excuse".. as in "ok" with the school.. and some schools can have very strict standards for attendance.  It's her first and 2nd day of her school.. not great to set her up to be 2 days behind.. 

At this point.. I don't see how BM will agree (no official letter to take her custody time is going to fly with her or the courts).. She wouldn't allow for you to let her miss ONE day.. now this is TWO?

At this point you have a few options.

1.  reschedule your trip so that she will be able to go.

2.  Your DH can decline his visitation that weekend and she can stay with mom and miss the whole trip.

3.  Your DH can drive to pick her up and drop her off (missing a good chunk of your trip.

4.  You can shorten your trip so that is not an issue.

Ideally you change the date.. but it may be that she will just miss this trip with you guys.. This is a big learning lesson for him.. he needs to be aware of his kid's schedule before he plans (or allows you to plan) a trip like this.

In the end.. this is 100% on him for not planning properly.. 

He can ask BM.. (typing it as official makes zero difference really).. but I would expect she will say no because the girl should not be missing the first two days of school (or 2 days period).. for a non-necessary reason.

I am not saying it's NEVER ok for a kid to miss school.. but I would say that it would be a very rare and special situation and it would more likely be later in the year where a kid's academic progress is more known.. and is thriving.. a camping trip would not generally rise to that.

Vacation time.  Move the camping trip so SD doesn't miss school.  Hard to miss the first two days. She will be so far behind her classmates.  That what parents do.

My kids miss school for vacations every year. I have no issues with it. Those experience are far more valuable than noses in books. My kids (stb16 and stb18) are smart and make up the work and have never had any fallout academically. 

As for what to do, there isn't much you can. If BM doesn't agree and she is the custodial parent there isn't anything you can do. 

I would however tell SD about the trip and make BM the bad guy for not allowing it. I would also give up the weekend or try and trade if BM won't let her go for the dates. Don't ruin your trip because BM won't allow extra time and experiences for their daughter! 

I think if she agrees to it than your BF needs to be amendable if BM takes SD out of school for a few days on her schedule.  Hopefully she is willing to work with you.  Personally we have always taken our kids out of school for vacations, our school district refuses year round school and I refuse to travel when it’s the hottest part of the year and the highest prices. 

In order to be an excused absence, you need approval 30 days before the trip here & you need to prove it will be educational. I did it once or twice when snow days were added to the end of the school year. SD spent most of the summer with BM so our choices were limited. 

Many years ago there was a poster named OrangeCounty. He is/was a Super smart man.  I often wonder what became of him. Anyway, he said the following.

Do not ask for any changes and do not give any changes.  He was right. We learned that lesson the hard way. 

Stick with the court order. 

Don't ask bm--- MIL was kind enough to switch her dates, but frankly if I were her, I would switch it back to Labor Day in 2024.  

Orange County's wisdom was simple. 

Good Luck.

*you realize emergencies are a different story, right?. Then again, bm may hold the line too*

Dont bother. Cancel the trip or cancel the visitation but there wont be any accomodation from BM on stuff like that. I would cancel the visitation and just go enjoy my vacation with my family but thats just me! Lol