Lazy Loading, LCP & Core Web Vitals: What South African Websites Need to Know
For years, web developers have relied on lazy loading to improve site performance. By delaying the loading of off-screen images, pages appear to load faster and reduce bandwidth consumption. But recent insights from Google’s own team highlight an important caveat: lazy loading can actually delay your Largest Contentful Paint (LCP) — one of the most important Core Web Vitals metrics.
For South African businesses, where mobile-first browsing and variable internet speeds are the norm, understanding this trade-off is essential for maintaining both user experience and SEO performance.
What Are Core Web Vitals?
Core Web Vitals are a set of user experience metrics used by Google to evaluate website performance:
- Largest Contentful Paint (LCP): How quickly the main content loads (target < 2.5s).
- Interaction to Next Paint (INP): How fast the page responds to user input (target < 200ms).
- Cumulative Layout Shift (CLS): How visually stable the page is while loading (target < 0.1).
Of these, LCP is especially critical because it reflects when the primary content becomes visible to users.
How Lazy Loading Works
Lazy loading delays the loading of non-critical images until they are about to appear on the screen. This saves bandwidth and can improve performance, especially on content-heavy sites.
Example: Instead of loading 20 product images at once, only the images visible above the fold load initially. Others load as the user scrolls.
The Problem: Lazy Loading and LCP
While lazy loading has clear benefits, applying it incorrectly can harm your LCP score.
Why?
- If the LCP element (often a hero image, banner, or product photo) is marked for lazy loading, the browser delays fetching it.
- This means the most important content — the one Google uses to calculate LCP — appears later than it should.
Result:
- Slower LCP times, lower Core Web Vitals scores, and potentially worse SEO rankings.
Best Practices: Balancing Lazy Loading and LCP
1. Don’t Lazy Load Critical Images
- Exclude above-the-fold images (hero banners, featured products, logos).
- Always preload or prioritise the image likely to be your LCP element.
2. Use Native Lazy Loading (loading="lazy")
- Modern browsers support native lazy loading, which is often more efficient than third-party scripts.
3. Implement Image Preloading
- Use
<link rel="preload">in your HTML for the LCP image. - This ensures it loads quickly, even if other images are lazy loaded.
4. Monitor with Search Console & CrUX
- Track Core Web Vitals South Africa performance data in both Google Search Console and the Chrome User Experience Report (CrUX).
- Look for LCP delays specifically tied to lazy loading.
South African Context: Why This Matters
- Mobile-First Market: Over 70% of South African web traffic comes from smartphones, where bandwidth and speed can vary.
- E-Commerce Growth: Product-heavy sites rely heavily on images — making lazy loading useful but risky if not applied correctly.
- Tourism & Hospitality: Hero images showcasing destinations or services often serve as the LCP element — and must load fast for global visitors.
Getting the balance right between performance savings and LCP optimisation is critical for local businesses competing online.
Action Plan for Developers and SEO Teams
- ✅ Identify your LCP element on key pages.
- ✅ Ensure that element is not lazy loaded.
- ✅ Preload critical images and fonts.
- ✅ Test performance using tools like PageSpeed Insights and Lighthouse.
- ✅ Continuously monitor Core Web Vitals reports for fluctuations.
Partner with Technical SEO Experts
Balancing lazy loading and LCP is a technical challenge that requires both development and SEO expertise. Incorrect implementation can unintentionally harm rankings and user experience.
EC Business Solutions helps South African companies optimise site speed and Core Web Vitals through Professional SEO Agency services — ensuring your website is fast, stable, and SEO-ready.
Conclusion
Lazy loading remains a valuable tool for performance optimisation, but if applied without care, it can hurt one of the most important Core Web Vitals metrics: Largest Contentful Paint (LCP).
For South African businesses, the rule is clear: lazy load secondary content, but never your critical, above-the-fold elements. By balancing both, you can achieve the best of both worlds — fast-loading sites and strong SEO visibility.
