Show Product Categories in WooCommerce Breadcrumbs

To display the product category in WooCommerce breadcrumbs, add the following code to your child theme’s functions.php file:

/**
 * Show product categories in WooCommerce breadcrumbs
 */
// Get breadcrumbs on product pages that read: Home > Shop > Product category > Product Name
add_filter( 'woo_breadcrumbs_trail', 'woo_custom_breadcrumbs_trail_add_product_categories', 20 );

function woo_custom_breadcrumbs_trail_add_product_categories ( $trail ) {
  if ( ( get_post_type() == 'product' ) && is_singular() ) {
		global $post;

		$taxonomy = 'product_cat';

		$terms = get_the_terms( $post->ID, $taxonomy );
		$links = array();

		if ( $terms && ! is_wp_error( $terms ) ) {
		$count = 0;
			foreach ( $terms as $c ) {
				$count++;
				if ( $count > 1 ) { continue; }
				$parents = woo_get_term_parents( $c->term_id, $taxonomy, true, ', ', $c->name, array() );

				if ( $parents != '' && ! is_wp_error( $parents ) ) {
					$parents_arr = explode( ', ', $parents );

					foreach ( $parents_arr as $p ) {
						if ( $p != '' ) { $links[] = $p; }
					}
				}
			}

			// Add the trail back on to the end.
			// $links[] = $trail['trail_end'];
			$trail_end = get_the_title($post->ID);

			// Add the new links, and the original trail's end, back into the trail.
			array_splice( $trail, 2, count( $trail ) - 1, $links );

			$trail['trail_end'] = $trail_end;
		}
	}

	return $trail;
}

/**
 * Retrieve term parents with separator.
 *
 * @param int $id Term ID.
 * @param string $taxonomy.
 * @param bool $link Optional, default is false. Whether to format with link.
 * @param string $separator Optional, default is '/'. How to separate terms.
 * @param bool $nicename Optional, default is false. Whether to use nice name for display.
 * @param array $visited Optional. Already linked to terms to prevent duplicates.
 * @return string
 */

if ( ! function_exists( 'woo_get_term_parents' ) ) {
function woo_get_term_parents( $id, $taxonomy, $link = false, $separator = '/', $nicename = false, $visited = array() ) {
	$chain = '';
	$parent = &get_term( $id, $taxonomy );
	if ( is_wp_error( $parent ) )
		return $parent;

	if ( $nicename ) {
		$name = $parent->slug;
	} else {
		$name = $parent->name;
	}

	if ( $parent->parent && ( $parent->parent != $parent->term_id ) && !in_array( $parent->parent, $visited ) ) {
		$visited[] = $parent->parent;
		$chain .= woo_get_term_parents( $parent->parent, $taxonomy, $link, $separator, $nicename, $visited );
	}

	if ( $link ) {
		$chain .= '<a href="' . get_term_link( $parent, $taxonomy ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $parent->name ) ) . '">'.$parent->name.'</a>' . $separator;
	} else {
		$chain .= $name.$separator;
	}
	return $chain;
	}
}

For more on breadcrumbs, see Adding Breadcrumbs to WordPress.