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South32 vs Rio Tinto shares: which ASX mining stock is better?
When you think of big-name Australian mining shares, it's hard to look past South32 Ltd (ASX: S32) and Rio Tinto Ltd (ASX: RIO). Both are resource powerhouses, but they've taken different approaches to growth, dividends, and the commodities they dig up. If you're weighing up South32 vs Rio Tinto shares for your portfolio, here's what stands out.
The case for South32
South32 emerged from BHP's 2015 demerger and now runs mining operations across ten countries, extracting everything from bauxite and aluminium to copper, silver, zinc, nickel, and manganese. According to its most recent company description, it employs around 9000 people and provides the raw materials crucial for construction, energy, renewables, and consumer products worldwide.
Among South32's fundamentals, a few things jump out. Its P/E ratio sits at 14.79, putting it in the reasonable valuation camp—neither super cheap nor stretched. The company's year-to-date (YTD) return is a real eye-catcher: up 38.07%, a hefty gain for any mining stock. Its dividend yield is a modest 1.94%, but it comes fully franked—a plus for Aussie income hunters. Over recent years, dividends have been consistently franked at 100%, and recent payouts, while not the highest, have shown reasonable regularity.
The case for Rio Tinto
Rio Tinto needs little introduction: this is one of the world's largest and oldest mining operations, tracing its roots to 1873. Listed on the ASX since 1962, Rio focuses on three major pillars—iron ore (its biggest earner), aluminium and lithium, and copper. The group also dabbles in other critical minerals through exploration and development, making it a true heavyweight in global resources.
Looking at Rio Tinto's metrics, scale is the first thing that stands out. With a market cap of $61.82 billion, it dwarfs South32. Rio also offers a more generous dividend yield at 4.07%, again fully franked. Earnings per share are much higher (7.382 vs South32's 0.235), consistent with its size and profitability. The P/E ratio is slightly higher at 15.94, but still sits in a similar band—a sign that you're not paying a huge premium for the blue-chip name. YTD, Rio's return is 16.56%: less blazing than South32's, but still a solid result considering its scale.
Valuation comparison
There's enough difference across important metrics to pop them into a table for an at-a-glance check:
| Metric | South32 | Rio Tinto |
|---|---|---|
| Market Cap | $22.48 billion | $61.82 billion |
| P/E Ratio | 14.79 | 15.94 |
| Dividend Yield | 1.94% (100% franked) | 4.07% (100% franked) |
| Earnings per Share | 0.235 | 7.382 |
| Dividend per Share | 0.13 | 6.70 |
| Year To Date Return | 38.07% | 16.56% |
Rio commands a huge lead in size, dividends, and profit per share. South32 is a smaller, more diversified operator and has delivered outsized returns so far this year.
Recent share price performance
Let's look at how the share prices have moved in recent weeks. Both companies' price history data covers the same date range: from 18 August to 16 September 2026.
South32 started on 18 August at $4.82 and finished on 16 September at $5.01. That's a gain of about 3.9% over this short period, consistent with its strong year-to-date performance. Rio Tinto started this period at $167.40 (18 August), ending at $166.25 on 16 September—a slight drop of roughly 0.7%. While Rio had some up days, the overall trend recently has been a touch negative.
It's worth noting, South32 has enjoyed a positive burst inline with its year-to-date trend, while Rio has flattened out.
Which is the better buy?
If I had to pick between South32 and Rio Tinto right now, my lean would be toward South32. Here's why: Its huge 38% YTD gain stands out—it's been a clear outperformer, and the recent price momentum shows buyers remain enthusiastic. While its dividend isn't as juicy as Rio's, it's fully franked and shows reasonable consistency.
Rio Tinto is a true blue-chip, offering scale, stability, and a far bigger dividend—great reasons for conservative, income-focused investors to be interested. But its recent share price has drifted sideways or down, and it lags South32 in YTD returns.
For those seeking growth and recent market momentum, South32 is my pick. But if you value big, steady dividends and market dominance, I can completely understand going with Rio. With both stocks offering 100% franking and trading at similar valuations, the edge for me goes to South32 on its current performance and uptrend.
