There are several spots in Langebaan for kitesurfing, but I'd like to share my experience about the two places I like the most in Langebaan for kitesurfing.
Location of Langebaan
Langebaan is located on the west coast of South Africa. It's about a 1.5-hour drive from Cape Town center to Langebaan. If you like flat water, it's definitely worth the drive. I always drive from Blouberg to Langebaan and sometimes enjoy taking a route through a nature park towards Langebaan. This nature park is called West Coast National Park. I have seen turtles, flamingos, a giraffe, and many other birds in this nature park. There are also beautiful beaches with warm water, which is nice to visit. However, you have to pay a small fee to enter the nature park, but it's definitely worth doing once if you're heading towards Langebaan.

Google maps location: Langebaan
Langebaan beaches
I always kitesurf at two places. One spot in Langebaan is called The Main Beach, and the other spot is called Shark Bay. The Main Beach is much larger than Shark Bay. Both beaches are surrounded by flat water, and despite being crowded, there's always a spot for everyone to kitesurf peacefully.
The water in Shark Bay is flatter than that in Main Beach. Warm water plus the name Shark Bay... you guessed it, there are a lot of sharks here. Just kidding. Despite its name, I've never seen a shark here and I feel very safe. You can easily see into the water and see what's swimming beneath you.
Shark Bay has a very small beach, making it a bit more difficult to place your kite. It's also surrounded by prickly bushes, and if you don't lay your kite down properly and hit these bushes, as one of my friends did, it's bye-bye kite. If you want more space for your kite on the beach, then I suggest going to Main Beach. Here, there's a large beach and more parking available. There are also many food and drink restaurants, which is nice to sit at after a kitesurfing session. Shark Bay has had a small café for a year now where you can sit and have a drink after your kitesurfing session. However, it closes in the late afternoon.
Conditions in Langebaan
I'm always in Cape Town from November to January. During this period, I sometimes also kitesurf in Langebaan. In this period, the wind blows at about 10 to 25 knots in Langebaan. Sometimes, it can be very windy here, up to 40 knots. For me, 10 to 25 knots is perfect. If it's windy in Blouberg, it's always a bit less windy in Langebaan. If I see that I can kitesurf in Blouberg, but prefer flat water, I often know that I have another option. I always kitesurf with my 7-meter kite at this spot. I often go with my friends who are better at kitesurfing and are larger then me. They often kitesurf at this spot with a 9 to 12-meter kite. The wind sometimes comes in gusts. Since I can't do extreme big air tricks, these gusts don't put me in danger when I want to land a trick, and I don't have much trouble with them.
This spot is very accessible for beginner kiters, and many schools are also present there. You can get the best lessons here in Cape Town because the water is shallow, so you can stand everywhere, which gives beginners a safe feeling. I recommend that if you're not a beginner kiter, kite a bit further from the beach. The kites of beginner kiters sometimes crash hard at the beginning of the beach. Besides big air kitesurfers, there are also many freestylers to be found on the water.
What wetsuit in Langebaan
The water temperature is about 16 to 25 degrees. I'm here in the summer, and for me, it varies per day what I like to wear. I prefer to wear a long wetsuit with a thickness of 5/3, but I have also kitesurfed in Langebaan with a short wetsuit. It also depends on how hard the wind blows. If it's windy and the water is warm, I still get a little cold from the wind, and I like to kite with a long wetsuit.
If you have any questions about kitesurfing in Langebaan, let me know. I hope to see you in Langebaan sometime, and then we can kite together.