Sparkling water, soda water, mineral water, seltzer, tonic: They all fizz, but they're not the same drink, and the differences decide which one belongs in your glass. In short, the gap comes down to where the bubbles come from, what minerals are inside, and whether anything (sugar, salts, quinine, fruit) has been added. This guide sorts them out in plain terms so you can order and shop with confidence, wherever you are.
TL;DR: All these drinks are carbonated water; the difference is what's added. Seltzer is plain carbonated water with nothing else. Club soda has added minerals for taste. Mineral water is naturally sourced with its own minerals (and is sometimes naturally carbonated, like Perrier). Tonic water contains sugar and quinine - it's the only one that's really a soft drink. Fruit sparkling water adds real fruit or flavor to carbonated water, ideally with no sugar.
The quick comparison
| Drink | What it is | Added ingredients | Typically sweet? |
|---|---|---|---|
| Seltzer | Plain water with added carbonation | None | No |
| Club soda / soda water | Carbonated water with added minerals/salts | Minerals (e.g. sodium) | No |
| Sparkling mineral water | Water from a mineral spring, sometimes naturally carbonated | Nothing added (minerals are natural) | No |
| Fruit sparkling water | Carbonated water with real fruit or flavor | Fruit/flavor; ideally no sugar | No (if no added sugar) |
| Tonic water | Carbonated water with quinine and sugar | Sugar + quinine | Yes |
Seltzer: the plainest fizz
Seltzer is the simplest of the group: plain water with carbon dioxide added, and nothing else. No minerals, no salt, no flavor. It's a blank canvas - clean and neutral - which is why flavored "seltzers" build on it. If you want fizz with zero anything, this is it.
Soda water and club soda: fizz with a mineral edge
Soda water (often called club soda) is carbonated water with minerals added back in, such as sodium bicarbonate or potassium salts. Those minerals give it a slightly fuller, faintly savoury taste, which is why bartenders reach for it as a mixer. In Thailand, the local reference point is Singha Soda Water, made from artesian well water since 1935 and the country's top-selling soda water. The added sodium is worth knowing about if you watch your salt, but there's no sugar.
Mineral water: the natural one
Mineral water comes from a protected underground source and carries its own dissolved minerals, from the spring rather than a factory. Some mineral waters are naturally carbonated - Perrier and San Pellegrino are the famous examples - while others are still and sold as "sparkling" only after light carbonation is added. The appeal is the natural mineral character and a clean taste that suits food. In Thai, this is the น้ำแร่ (mineral water) category, and it's what many people picture first when they think "premium water."
Fruit sparkling water: flavour without the sugar
Fruit sparkling water is carbonated water with real fruit juice or fruit flavor added - the category that's growing fastest as people move off soft drinks. The key question here is sugar. Done well, it delivers real fruit taste with no added sugar and no sweeteners, so it drinks like a soft drink without being one. ZUZA is an example built this way: real Thai fruit juice, no added sugar, 0 calories per can in most flavors (drinkzuza.com, 2026), in flavors like lychee, calamansi, and passion fruit. Done poorly, "fruit" sparkling water is just soda with a splash of juice and a lot of sugar, so the label still matters.
Tonic water: the odd one out
Tonic water looks like the others but belongs in a different category. It contains quinine (which gives its bitter edge) and, crucially, sugar - often as much as a regular soft drink. That makes it the only drink on this list that's genuinely sweet and calorie-heavy in its standard form. Great in a gin and tonic; not a substitute for water.
Which is healthiest?
For plain hydration, seltzer and mineral water win by simplicity - carbonated water with nothing or only natural minerals added. Soda water is close behind, with a little added sodium. Fruit sparkling water with no added sugar is an excellent everyday choice if you want flavor, since the taste comes from fruit rather than syrup. Tonic water is the one to treat as a soft drink. Across all of them, the rule is the same: the bubbles are fine; check for added sugar and sweeteners.
FAQ
Is soda water the same as sparkling water?
Not exactly. "Sparkling water" is a broad term for any carbonated water, including mineral water and flavored versions. Soda water (club soda) is a specific type with added minerals or salts, used mainly as a mixer. All soda water is sparkling water, but not all sparkling water is soda water.
Is seltzer healthier than soda water?
They're very close. Seltzer is plain carbonated water with nothing added; soda water has a little added sodium for taste. Both are sugar-free and hydrating. If you're limiting sodium, seltzer or plain sparkling water has the edge.
Does tonic water have sugar?
Yes. Standard tonic water contains quinine and a significant amount of sugar, often similar to a soft drink. Diet or slimline tonics use sweeteners instead. Of all the fizzy waters, tonic is the one to treat as a treat, not a hydrator.
Is flavored sparkling water still just water?
If it has no added sugar or sweeteners, it's essentially carbonated water with fruit flavor, and it hydrates like water. Once sugar is added, it moves closer to a soft drink. The label tells you which side of the line it's on.
The bottom line
They all fizz, but they're not interchangeable: seltzer is plain, soda water adds minerals, mineral water is naturally sourced, fruit sparkling water adds flavor, and tonic adds sugar. Pick by what you want from the glass - and if it's fruit flavor without the sugar, a no-added-sugar option like ZUZA is the category to look in.
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