Thai font · OFL

LINE Seed Sans TH

LINE ซีด

By Narongsak Chaiwong

Typography & Licensing Specialist, ThaiGraph · October 19, 2026

Information verified as of October 2026

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What LINE Seed Sans TH is

LINE Seed Sans TH (Thai name “LINE ซีด”) is the loopless Thai version of LINE’s brand typeface. The Latin was designed by Dalton Maag, a type studio in London, and the Thai by Cadson Demak; it is free under the SIL Open Font License. Copyright belongs to LY Corporation (LY Corp.), per the licensing notice on the official site.

The Thai page of the LINE Seed site says LINE created LINE Seed TH in collaboration with Cadson Demak, and the English page says LINE worked with Dalton Maag to create LINE Seed as a whole. The font files spell the credit out: “Dalton Maag Ltd | Thai characters by Cadson Demak Co.,Ltd.”

LINE Seed shares one DNA across several scripts; the site offers five downloads, EN, JP, KR, TH and TW. The Thai version is designed to sit comfortably next to the English while keeping Thai character, and covers consonants, vowels, tone marks and Thai numerals.

How many weights LINE Seed Sans TH has

LINE Seed Sans TH has five weights — Thin, Regular, Bold, ExtraBold and Heavy — with no italics and no Light, Medium or SemiBold. These five match the type tester on the official site and the files in the Desktop folder that ThaiGraph inspected.

The gap to know about is between Regular (400) and Bold (700). If a UI needs a Medium for buttons or table headers, you choose Regular or Bold yourself, or use a nine-weight family such as Kanit or Prompt.

Where to download LINE Seed Sans TH

Download it only from seed.line.me, LINE’s official site: click Download and choose “LINE Seed TH” to get LINE_Seed_Sans_TH.zip, version 1.003. LINE’s Thai font is not on Google Fonts, whose catalogue carries only LINE Seed JP, and the line/seed GitHub repository holds sources for the Japanese version only.

The zip has four folders:

• Desktop — TTF and OTF in five weights, for installing on a computer for Word, PowerPoint, Adobe and Figma
• Web — WOFF2, WOFF and EOT for webfont use
• App — for apps, going by the folder name: the same letterforms as Desktop under the family name “LINE Seed Sans TH App”, with different vertical metrics
• Game — a single Bold file under the family name “LINE Seed Sans TH Game”

For desktop work, install the Desktop folder only. Installing App or Game as well adds extra names to your font menu. Download from seed.line.me rather than font aggregators or third-party packages, so you get the current files LINE publishes itself.

Is LINE Seed Sans TH free for commercial use?

Yes, for personal and commercial work. LINE releases it under the SIL Open Font License 1.1; the one prohibition is selling the font files, and attribution is a recommendation, not a requirement. LINE’s licensing notice says “You can use them for any personal or commercial purposes. However, the software font files themselves cannot be sold by the other parties other than LY Corp.”

• Logos and client work are fine — OFL FAQ 1.1 covers any kind of design work, logos included, with no further permission
• Webfont use is fine — OFL FAQ 2.1 allows loading through CSS @font-face
• PDF embedding is fine — 1.12 allows embedding in full or as a subset
• Attribution — LINE “highly recommend[s]” crediting the font in commercial products or services, but OFL FAQ 1.1.2 states credit is not required
• No selling the files on their own — bundling with software or documents is allowed, selling the files is not (OFL FAQ 1.4–1.6)

LINE’s notice ends by saying it is not legal advice and pointing to the full licence. Compare other licence types in the Thai font licensing guide.

The alternate leading vowels (ss01)

LINE Seed Sans TH includes an alternate set for the leading vowels เ แ โ ใ ไ, switched on with the OpenType ss01 feature. These alternates add a curved foot at the baseline, where the default forms are straight strokes. The official site says the alternate set can be chosen when you want easier reading in limited space; the list of substituted characters comes from ThaiGraph reading the GSUB table in the font file.

On the web, enable it with font-feature-settings: "ss01" 1; on the text. In design software with a stylistic-set menu, choose Set 1. The feature is optional; without it, the leading vowels are the default straight forms.

Using LINE Seed Sans TH on the web

Take the WOFF2 files from the Web folder and self-host them with @font-face — no permission needed, because the OFL allows webfont use. The font is not on Google Fonts, so there is no ready-made CSS link. Example for Regular and Bold:

@font-face {
  font-family: "LINE Seed Sans TH";
  src: url("/fonts/LINESeedSansTH_W_Rg.woff2") format("woff2");
  font-weight: 400;
  font-display: swap;
}
@font-face {
  font-family: "LINE Seed Sans TH";
  src: url("/fonts/LINESeedSansTH_W_Bd.woff2") format("woff2");
  font-weight: 700;
  font-display: swap;
}
body { font-family: "LINE Seed Sans TH", sans-serif; }

The file names match the Web/WOFF2 folder in the zip (Th = Thin, Rg = Regular, Bd = Bold, XBd = ExtraBold, He = Heavy). Load only the weights you use to keep pages light.

Using it in Word, PowerPoint, Canva and Figma

Install the files from Desktop/TTF and it works in Word and PowerPoint straight away, and it can be embedded in PowerPoint files in editable form, because its embedding permission is Editable. The Windows steps, per Microsoft: right-click the zip, choose Extract, then right-click the font files and choose Install.

• Word / PowerPoint — the files have fsType 8, which the OpenType specification defines as Editable embedding: recipients can open, edit and save with the embedded font. Embed fonts in the file is under File → Options → Save, per Microsoft.
• Canva — if a search of Canva’s font library does not find it, upload the TTF or OTF files to a Brand Kit, available on Pro, Teams, Business, Education and Nonprofits.
• Figma — not on Google Fonts, so install it locally and pick it from the “Installed by you” filter, per Figma’s help page.
• Phones — standard iPhone and Android cannot install it as a system font; see installing Thai fonts on a phone.

There are no italics in the family; pressing I in Word gives a faux italic the software slants itself.

Letterform design and size

LINE describes LINE Seed as a geometric typeface with some Gothic influences and an emphasis on simplicity, with the rounded corners of the LINE logo built into every letter, number, symbol and icon. The Thai version reduces detail and sets the spacing between consonants, vowels and tone marks for easy reading; the character set also includes LINE icons and symbols, per the Thai page.

On size, LINE Seed Sans TH is not small the way ThaiSans Neue is. ThaiGraph measured the height of น at 0.555 em, close to Noto Sans Thai and Kanit, so it can be set at the same size as Google’s Thai fonts.

LINE Seed’s Latin capitals are taller than any other font in the table. If your text mixes in a lot of English capitals (brand names, acronyms), check whether the Latin overpowers the Thai. The principles of balancing the two scripts are in the Thai-Latin bilingual typography guide.

LINE Seed Sans TH vs Kanit and Prompt

All three are loopless SIL OFL Thai faces with Cadson Demak behind them. Choose LINE Seed Sans TH for LINE’s friendly rounded tone and a Dalton Maag Latin in the same file; choose Kanit or Prompt for nine weights, italics and delivery through Google Fonts. The real differences are weight count and distribution.

If you prefer a technical tone to a friendly one, try Anuphan. See every loopless face in loopless Thai fonts, and more of Cadson Demak’s work in the Cadson Demak catalogue.

Best uses

LINE Seed Sans TH suits apps, websites and digital media that want a friendly, readable tone with Thai and English in one file. Good fits:

• App and web interfaces that want a loopless Thai face with ready-made WOFF2 files
• Headlines and banners in ExtraBold or Heavy
• Marketing material that wants a rounded, consumer-product personality

Poor fits: work that needs italics, UI that needs a Medium or SemiBold, and long body text. Héctor Mangas’s experiments, published by Typotheque, conclude that “For settings where more texts is presented, looped is preferred for all users”, so pair it with a looped face for body text.

Pairings

LINE Seed Sans TH does its best work in headlines and UI; pair it with a looped or serif face for long text. Two pairings that work:

• Sarabun — looped Thai body text under LINE Seed Bold or ExtraBold headlines
• Noto Serif Thai — editorial work that wants contrast between a geometric headline and a serif body

See every free Thai font cleared for commercial use in free Thai fonts, or browse the full Thai font library.

Information verified as of October 2026