The short answer
ClassForKids, Bookeo, TeamUp and Sawyer. All four handle what a baby class business actually sells, which is a term rather than an appointment: age-banded classes, trial sessions, block enrolment, registers and waitlists.
A general appointment tool built for haircuts or consultations will take a booking, but it cannot hold a term as a block with a capped register, and that is the whole job.
Pick by your situation
A UK provider running terms across a few halls. ClassForKids. It was built for children's activity providers in the UK, and terms, registers, trials and waitlists are the core of it rather than an add-on.
A US or Canadian provider. Sawyer. It combines booking software with a parent-facing marketplace, which brings some discovery alongside the admin.
You already run adult fitness or a studio timetable alongside the baby classes. TeamUp, because memberships, courses and recurring timetables sit in one place and you are not paying for two systems.
You need unusual rules, several currencies or heavy customisation. Bookeo, which is the most configurable of the four and the least opinionated about what a class is.
You are a franchisee of a national brand. Ask first. Many franchises mandate a central booking system, and your website's job is then to point cleanly at it rather than to replace it.
If you already run something that works, stay on it. Moving a customer list, live term bookings and a year of registers mid-term is a genuine cost and rarely repays itself unless something is actually broken. Move between terms, never during one.
The six things any of them has to do
Judge the platform against this list rather than a feature page.
1. Sell a term as a block. Eight or ten weeks, one payment, one register, with the dates visible to the parent before she pays.
2. Enforce an age band. From the baby's date of birth, so a parent cannot book a five-month-old into a crawlers class by mistake and so the record stays right as the baby grows.
3. Take a trial as a single session. Consuming a space in a named week, then converting to term enrolment with one link.
4. Cap capacity per venue. A church hall and a leisure centre studio do not hold the same number of babies and buggies.
5. Run a waitlist. With a decision about whether it promotes automatically when a place frees.
6. Handle joining mid-term. Pro rata, without you working out the arithmetic by hand in a message thread.
Anything beyond that list is convenience. Anything missing from it becomes your Sunday evening.
What generic tools get wrong
A contact form, a spreadsheet or a general calendar app can take a request. None of them can hold a term.
What you lose is specific. No register, so you print a list and mark it by hand. No age check, so the wrong baby is in the wrong room. No capacity cap, so a class oversells and someone is turned away at the door. No waitlist, so a place that frees on a Tuesday goes unsold. No enrolment link, so every trial-to-term conversion is a message you have to remember to send. The booking looks like it works, and the operational cost lands quietly on you.
Confirm the specifics of any feature with the vendor before you build a page around it, because these platforms change what they offer release to release.
What the website has to do about it
The platform is the register. The website's job is to get a tired parent into it in one tap and to make the age band and the price known first.
That means classes listed by age band with the developmental focus explained. It means the price stated rather than hidden behind an enquiry. It means a Book a trial button on every class page, deep linked to that class rather than to a general timetable. It means one booking page carrying any embed rather than a widget loading in the footer of the whole site. And it means the whole route tested inside the Instagram in-app browser, because a large share of baby class traffic arrives from a link in bio and that is where payment steps fail silently.
On marketplaces
Sawyer's marketplace and the local class directories bring real discovery, especially for a new provider with no search presence yet.
The trade-off is that a directory listing competes with your own site for your own name, and the parent relationship sits partly with the platform. Use the traffic, keep your own site as the place people find your prices, your venues and your first-class page, and make sure your own booking link is the one on your Instagram profile.
Where this sits
Wiring ClassForKids, Bookeo, TeamUp or Sawyer into a site that already answers the age band and the price question is the core of every baby class website we build, and the same approach runs through our wider childcare and family websites. The packages are on pricing. Choose the platform for the register, then let the site do nothing but open it.