Hello @Rp1,
There is a way to block checkin on a specific date, say 14th of June, as opposed to specific days like all Mondays, while allowing guests to stay through that date. It's a bit indirect and requires that you enable the rule-sets feature. Hence this message is a bit long but the procedure does work. I've tested it on my own listing.
First enable rule-sets.
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I did it by going to the link below.
https://www.airbnb.com/hosttools
On that page scroll down to the "Work the way you want" section and click on "Use the tools now" link. On the next page scroll to the "reservations" section and click on "Use the multi-calendar".
It then set the multicalendar as the default calendar view even though I have only one listing.
To see the full size month calendar view click on a listing's title. You can then click on the date for you wish to disallow checkins.
Now create a rule-set for the date you wish to block checkin on.
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It is possible, using rule-sets, to set no checkins on a particular date while allowing guests to stay through that date.
You create a rule-set that disallows checkins on whatever day of the week the date is and then apply it to that date.
Go to the month view of your calendar and click on the date. In the box that appears on the right scroll down and click in the "Rule-sets" box and choose "Add rule-set". Then scroll down to the "Availability" section and click on "Customise" for the "Check-in and checkout days". Now check the "Guests can't check in on" box for the day of the week corresponding to your desired date. Then click "Save" and "Save" again.
I tried it for my listing for the 27th of August which is a Monday so I selected that guests can't check in on Mondays. When I searched for my listing on the map it then allowed me to select a checkin date of the 26th of August and checkout on the 28th but, as hoped, didn't allow selecting a checkin on the 27th.
It does, of course show the problem highlighted by Zappa, meaning that guests will see your calendar marked as if that day is blocked. That is the calendar's visual representation doesn't differentiate between a fully blocked date and one that's blocked only for checkins 😞
Steve.