The short answer: yes, in specific ways
Yes, website design affects SEO, but not in the way many sales pitches suggest. Search engines do not reward a site for looking modern or penalise it for a colour scheme.
They respond to what design decisions do to the page: whether the mobile version shows the full content, how fast the page loads and settles, whether the structure makes the important pages easy to find, and whether the text can actually be read by a crawler.
The four biggest levers are:
- The mobile layout, because it is the version Google primarily uses for indexing.
- Speed and stability, which are shaped by hero images, fonts, video and animation choices.
- Structure and navigation, which decide how link value and crawlers flow through the site.
- Readable content, meaning real text in proper headings, not text baked into images.
Then there is the risk most owners only learn about afterwards: a redesign that changes URLs without redirects can lose a large share of search traffic within weeks. The sections below take each lever in turn, using Google's own documentation rather than guesswork. For more on the technical side, browse our articles on SEO, speed and analytics.
Mobile layout comes first
Google uses mobile-first indexing: it primarily crawls and indexes the mobile version of a page. For design, that has a blunt consequence. If something is on the desktop layout but dropped from the mobile layout to save space, Google may not count it.
The pattern is common on sites designed desktop first and squeezed down afterwards:
- a service description trimmed to one line on mobile;
- a desktop sidebar with links to key pages that disappears on phones;
- a table of prices or rooms replaced by a "view on desktop" note;
- structured data or image alt text present only in the desktop template.
The fix is to design the mobile layout as the main version. The same content, headings and links should exist on both, even if the mobile layout stacks or collapses them. Tap targets need room, text needs to be readable without zooming, and pop-ups should not cover the content as soon as the page opens. In Bangkok this is not a technical nicety: many of your customers will first see your site on a phone, often after tapping a link in LINE or Google Maps.
Speed is a design decision
Google's page experience guidance includes Core Web Vitals: how quickly the main content appears (Largest Contentful Paint), how quickly the page responds to a tap (Interaction to Next Paint), and how much the layout jumps while loading (Cumulative Layout Shift). Google describes these as signals among many, and relevant content still comes first. But each of the three is largely decided in the design phase, long before a developer can optimise anything. To see where your own pages stand, learn how to read a speed test and the Core Web Vitals report.
Where design choices cost speed
- Hero media. A full-screen video or a 4 MB photo at the top of the homepage is usually the Largest Contentful Paint element. A well-compressed still image, sized for mobile, loads far faster. The file side is covered in our guide to image optimization for business sites.
- Fonts. Several families and weights, plus a separate Thai font, add up quickly. Choose one Latin and one Thai family, limit the weights, and make sure the Thai font includes the characters and vowel marks you need.
- Animation and sliders. Heavy scroll effects and carousels add JavaScript and can delay interaction on mid-range phones.
- Layout shift. Banners, cookie bars and images without reserved space push content down as they load.
Delivery matters too: a CDN in front of the host helps static files reach visitors faster, as our article on what Cloudflare adds in front of your host explains. But a CDN cannot make a heavy design light.
Structure, navigation and internal links
How pages are grouped and linked is information architecture, and it is part of design whether or not anyone calls it that. Search engines find and weigh pages largely through links. A page linked from the main menu and from related pages is treated as more important than one reachable only through a search box or a footer link five levels down. Our guide to planning your website structure shows how to group pages before design starts.
Patterns that help
- A main menu that names your core services or product ranges in the words customers use, not internal jargon.
- A shallow hierarchy: important pages within two or three clicks of the homepage.
- Links inside the text of pages, pointing to related services, guides and prices, with anchor text that describes the destination.
- Breadcrumbs on deeper pages, so both people and crawlers see where a page sits.
Patterns that hurt
- Menus built only from icons or images with no text.
- Important pages reachable only through filters, forms or on-site search.
- Mega menus linking to hundreds of thin pages, which dilutes attention across pages that do not deserve it.
- Orphan pages, such as a campaign or location page that nothing links to.
Platform settings also play a part, and they differ: our WordPress SEO guide for business websites covers archives and plugins, and the Shopify SEO guide for Thai stores covers collections and fixed URLs.
Headings, text in images and hidden content
Designers work visually. Search engines read the code. A few common design habits create a gap between what a visitor sees and what a crawler understands.
Headings chosen for looks
Headings should describe the structure: one H1 for the page topic, H2s for sections, H3s beneath. When heading tags are picked for their font size, a page can end up with five H1s or a slogan as its main heading, and the real topic sits in plain paragraph text.
Text inside images
A banner that says "Aircon cleaning in Lat Phrao, book today" as part of a JPEG is weak for search. Google can extract some text from images, but it relies on HTML text to understand a page, and screen readers cannot read the words at all. Put headlines, prices and service names in real text over the image, and use alt text to describe the picture.
Tabs, accordions and sliders
Content inside tabs or accordions that is in the HTML can be indexed, so an FAQ accordion is fine. The risk is content that only loads after a click, fetched by JavaScript. Sliders are a softer problem: anything on a later slide depends on the visitor waiting or clicking, so do not put your main message on slide three.
JavaScript-rendered content
Google can render JavaScript, but rendering can happen later than crawling, and other search engines and many AI crawlers render less reliably. For a business site, the main text, links and headings should be in the HTML the server sends.
Design that builds trust
Google's guidance on helpful content asks whether a page makes it clear who is behind it and why a visitor should trust it. Design decides whether that information is easy to find or buried.
- Visible contact details. Address, phone, email and opening hours in the footer and on a proper contact page, matching your Google Business Profile.
- A real about page. Who runs the business, what it does, where it is. Not three paragraphs of generic mission statement.
- Honest photos. Your premises, products and staff where possible. Stock photos of handshakes add nothing, and a visitor comparing clinics or hotels in Bangkok notices.
- Clear policies. A privacy notice and cookie consent that meet PDPA, plus delivery and returns terms for shops.
Accessibility and Thai readability
Much of what makes a site accessible also makes it easier for search engines to read: real text, a logical heading order, alt text on meaningful images, labelled form fields and enough contrast. For Thai text, typography needs extra care. Thai script stacks vowels and tone marks above and below the line, so line height must be generous, and font sizes that work for English often look cramped in Thai. Thai has no spaces between words, so long lines and justified text make reading harder on mobile. A bilingual site should set these separately for each language rather than sharing one style.
Where do redesigns lose rankings?
The classic story goes like this: a business launches a new website that looks far better than the old one, and within weeks enquiries from Google drop. The design is rarely the cause. The cause is what changed underneath: URLs that moved without redirects, pages that were merged or deleted, text that was cut to make the layout cleaner, or titles and headings that were lost in the rebuild.
Google's documentation on site moves with URL changes is clear that each old URL should redirect with a 301 to its closest new equivalent. Redesign drops usually trace back to skipped steps in the list below, so treat it as part of the design project, not an afterthought.
- List every current URLExport the sitemap and crawl the old site. Note which pages get search traffic in Search Console.
- Keep URLs where you canThe safest redirect is the one you never need. Change URLs only for a clear reason.
- Map and redirect the restEach old URL gets a 301 redirect to its closest new page, not to the homepage.
- Keep the content that ranksDo not cut text from pages that bring traffic just to make the layout tidier. Restructure it instead.
- Carry over titles, headings and schemaMove the SEO titles, descriptions and structured data that were working.
- Check the staging site is blocked, and the live site is notStaging should be hidden from search; the noindex setting must be removed at launch.
- Test and watch after launchCrawl the new site for broken links and 404s, resubmit the sitemap, and watch Search Console for several weeks.
Which design choices does Google not care about?
Some good news for owners who want a site that reflects their brand: a lot of design is simply not a ranking matter.
- Colours and visual style. Minimal or bold, dark or light, search engines do not score taste. Contrast still matters for readability.
- Whether the site looks "modern". An older-looking site with fast pages, clear structure and useful content can outrank a beautiful one that is slow and thin.
- Which platform built it, as long as the output is clean, fast and crawlable.
- Illustrations versus photos, provided both have sensible alt text where they carry meaning.
So choose the style that fits your customers, then make sure the build underneath respects the rules above. That is how we approach custom website design for Bangkok businesses: mobile layout first, real text in real headings, light pages, and a structure mapped to how people search. Our Starter package, from THB 10,000, includes a custom design with on-page SEO for up to 5 pages; Business, from THB 30,000, adds English and Thai, a custom theme with no page builder, keyword mapping and schema markup for up to 15 pages. Both prices are indicative and one-time, and a typical project takes around 15 days.
Planning a new site or a redesign? Ask for a price for your project, or WhatsApp or call +66 93 004 4098, every day from 10:00 to 19:00 Bangkok time. We build the site; we do not sell ongoing SEO retainers.
Who reviewed this guide
Who builds your site
Litesh Dhir
Builds and ranks the websites: the systems behind the 17 client sites whose Search Console numbers we publish.
More about usMore SEO and speed articles
Sources
- Google Search Central: Mobile-first indexing best practices
- Google Search Central: Understanding page experience
- Google Search Central: JavaScript SEO basics
- Google Search Central: Site moves with URL changes
- Google Search Central: Creating helpful, reliable, people-first content