Change Bootstrap Carousel fade transition

Question

There are several questions asked on Stackoverflow regarding Carousel fade transition but none of them seem to work on a default 4.0.0 implementation:

<div id="carouselExampleIndicators" class="carousel slide" data-ride="carousel">
  <ol class="carousel-indicators">
    <li data-target="#carouselExampleIndicators" data-slide-to="0" class="active"></li>
    <li data-target="#carouselExampleIndicators" data-slide-to="1"></li>
    <li data-target="#carouselExampleIndicators" data-slide-to="2"></li>
  </ol>
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img class="d-block w-100" src="..." alt="First slide">
    </div>
    <div class="carousel-item">
      <img class="d-block w-100" src="..." alt="Second slide">
    </div>
    <div class="carousel-item">
      <img class="d-block w-100" src="..." alt="Third slide">
    </div>
  </div>
  <a class="carousel-control-prev" href="#carouselExampleIndicators" role="button" data-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="sr-only">Previous</span>
  </a>
  <a class="carousel-control-next" href="#carouselExampleIndicators" role="button" data-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="sr-only">Next</span>
  </a>
</div>

Did bootstrap change the way of transitioning carousel-item -s since Alpha.6 version? How would one go about implementing the fade transition instead of slide in 4.0.0 ?

Answer 1

Bootstrap 5 Carousel Fade (update 2021)

Bootstrap 5 includes a "fade" effect that can be used by simply adding the carousel-fade class to the Carousel. By default, the transition duration is .6s. To increase the duration, and make the fade between slides slower, override the transition timing on the CSS...

/* change transition duration to control the speed of fade effect */
.carousel-item {
  transition: transform 2.6s ease-in-out;
}

.carousel-fade .active.carousel-item-start,
.carousel-fade .active.carousel-item-end {
  transition: opacity 0s 2.6s;
}

Bootstrap 5 Carousel Fade Slower

---

Bootstrap 4.0 Carousel Fade (original answer)

.carousel-fade .carousel-item {
 opacity: 0;
 transition-duration: .6s;
 transition-property: opacity;
}

.carousel-fade  .carousel-item.active,
.carousel-fade  .carousel-item-next.carousel-item-left,
.carousel-fade  .carousel-item-prev.carousel-item-right {
  opacity: 1;
}

.carousel-fade .active.carousel-item-left,
.carousel-fade  .active.carousel-item-right {
 opacity: 0;
}

.carousel-fade  .carousel-item-next,
.carousel-fade .carousel-item-prev,
.carousel-fade .carousel-item.active,
.carousel-fade .active.carousel-item-left,
.carousel-fade  .active.carousel-item-prev {
 transform: translateX(0);
 transform: translate3d(0, 0, 0);
}

---

The fade effect was removed from the carousel during the 4.0 Beta and is also not available in 4.0.0. This pull request indicates that the fade effect will return in 4.1 or 4.2. In the meanwhile, the above CSS will work for 4.0.0

https://codeply.com/go/LhLJlldsLN

Answer 2

To get the fade-in effect, you can add "carousel-fade" class to carousel's main div as below.

---

Update: Bootstrap 5

Bootstrap 5 is almost the same with Bootstrap 4 but the data-ride attribute is now data-bs-ride.

Bootstrap 5 example

<div id="carouselExampleIndicators" class="carousel slide carousel-fade" data-bs-ride="carousel">
...
</div>

---

Bootstrap 4 example

<div id="carouselExampleIndicators" class="carousel slide carousel-fade" data-ride="carousel"> 
....
</div>