BANGKOK, THAILAND – A Swiss visitor’s slow “5G” connection in central Bangkok highlighted how Thailand’s high-speed mobile revolution left many prepaid and tourist users struggling with throttled data and confusing tariffs.
Slow “5G” at a Bangkok mall
A Swiss tourist reportedly stood in front of Bangkok’s Terminal 21 mall with a brand-new smartphone that showed a 5G icon but delivered speeds closer to a sluggish 3G network. The issue was traced to his DTAC prepaid SIM, revealing a broader problem affecting thousands of visitors and residents. What looked like a technical fault emerged as a structural dilemma rooted in spectrum allocation, corporate consolidation and customer prioritisation.
Early 5G lead, limited spectrum
Thailand was regarded as an early mover in 5G deployment in Southeast Asia, with major operators launching commercial services in 2020. DTAC, then the country’s third-largest provider, advertised nationwide high-speed 5G access and showed smiling users surfing at “light speed.” In practice, the company secured only the 700‑megahertz band in the 2020 auction, a frequency with strong coverage and indoor reach but significantly lower speeds than the mid-band 2600‑megahertz spectrum obtained by rivals AIS and True Move.
Prepaid users at the back of the queue
Technical measurements underlined the gap: customers on AIS’s 2600‑megahertz band reached around 105 megabits per second, while DTAC users averaged roughly 30 megabits. This was described as the difference between a sports car and a moped on the data highway, leaving streaming, gaming and video calls barely usable. The problem was more acute for prepaid users – mainly tourists and occasional customers – who often had only restricted access to available 5G capacity, while contract plans from 349 baht a month were prioritised.
Merger with True Move reshapes the market
In March 2023, DTAC merged with True Move, creating Thailand’s largest mobile operator with about 55 million customers. The deal, valued at roughly 6.3 billion euros, left Norway’s Telenor Group and Thailand’s Charoen Pokphand Group each holding 30% stakes. The merger initially brought clear technical benefits, as DTAC subscribers suddenly gained access to True Move’s 2600‑megahertz spectrum and saw average download speeds jump from 29.6 to 82.1 megabits per second in March 2023.
Complex integration and confused customers
Integrating the two networks proved difficult, as engineers had to retune thousands of base stations, redistribute frequencies and harmonise IT systems. The National Broadcasting and Telecommunications Commission (NBTC) required both brands to remain separate for at least three years, prolonging the transition. During this phase, prepaid customers reported inconsistent experiences, including receiving True numbers instead of promised DTAC lines, unusable prepaid credit and voicemail or automated messages available only in Thai despite English language settings.
Economic logic behind a two-tier system
Industry practices placed postpaid customers with fixed contracts at the top of the priority list, as they generated predictable revenue. Prepaid users were treated as less valuable, with their data often throttled or shifted to slower frequencies when networks were congested. After the merger, the combined network had to serve a larger user base, and performance reportedly deteriorated during peak times in Bangkok and at major tourist destinations such as Phuket, leaving headline 5G speeds largely theoretical for many prepaid users.
High concentration, higher prices
The merger effectively reduced Thailand’s mobile sector to two big operators: AIS with about 47% market share and the merged True Corporation with 53%. The Herfindahl-Hirschman Index of market concentration rose to 4,820 points, far above the 2,500 threshold typically viewed as harmful to competition. Lower-cost plans disappeared shortly after, with True raising a 1,399‑baht package to 1,499 baht and DTAC increasing a 349‑baht plan with 20 gigabytes of data to 399 baht, in some cases while cutting data allowances.
Tourists face opaque 5G offers
At airports in Bangkok, Phuket and Chiang Mai, staff continued to promote DTAC tourist packages promising unlimited 5G data for 8, 15 or 30 days, priced between 449 and 1,199 baht. The glossy marketing did not highlight key restrictions, particularly for eSIM variants ordered online. These eSIMs operated only within Thailand and could be deactivated if installed before arrival, with activation required inside the country, ideally one day before use, a rule aimed at fraud prevention but confusing for less tech-savvy visitors.
“One Network” integration and patchy gains
In October 2025, True Corporation announced it had completed network integration under the “One Network” programme, aimed at removing redundant towers and improving efficiency. The company reported that DTAC users saw a 4.39‑fold increase in 5G speeds on the 2600‑megahertz band, while True customers recorded a 1.09‑fold improvement. Yet many prepaid users said these gains did not match their daily experience, as investments concentrated on profitable postpaid segments and major urban centres, while rural areas and outlying tourist routes remained underserved.
Average speeds mask wide disparities
Opensignal data from June 2025 showed AIS still leading 5G download speeds at 105.3 megabits per second, with 22.4 megabits for uploads. DTAC placed second with 90.3 megabits for downloads, followed by True Move at 84.3 megabits, and DTAC narrowly led in video streaming scores. However, these averages concealed wide differences between customer groups, with premium postpaid users regularly achieving advertised speeds while many prepaid, especially budget tourist SIM customers, reported effectively 4G-level performance despite a 5G icon.
Device compatibility adds another hurdle
Not all smartphones supported the original 700‑megahertz 5G band used by DTAC, creating further confusion. Apple devices from the iPhone 12 onward required at least iOS 14.5 and a specific carrier update, while many imported phones from China or the United States worked only partially on Thai 5G frequencies. DTAC offered a compatibility check on its website, but many tourists were unaware of it and bought SIMs at the airport without being told about these technical caveats.
Investment shifts and consumer warnings
Market concentration coincided with rising base tariffs and reportedly weaker incentives to expand coverage. True Corporation announced plans to achieve 98% 5G coverage by end‑2026, mainly focusing on Bangkok and economically important regions rather than remote islands like Koh Tao or distant national parks. Consumer groups had criticised the merger from the start and warned of exactly these outcomes – higher prices with stagnant or declining quality – while NBTC approved the deal with conditions that critics later described as ineffective.
Limited alternatives for dissatisfied users
Customers unhappy with DTAC’s 5G performance had only a few options in a two‑player market. A switch to AIS offered what was described as the best network quality, with investment in 5G reaching 95% of the population and tourist SIMs priced from 299 to 899 baht for 8 to 30 days, including 15 to 50 gigabytes of data and free access to social media services. True Move remained the other main option, offering tourist SIMs between 449 and 1,199 baht with promises of unlimited data and calls, though actual performance varied significantly by location.
New spectrum auction, old incentives
In June 2025, regulators auctioned 450 megahertz of spectrum across seven bands, including the 2100‑ and 2300‑megahertz ranges important for 5G. The allocation was expected to reinforce the dominance of AIS and True Corporation, as both were likely to secure the most attractive licences. For prepaid users, the economic incentives remained unfavourable, as tourists generated only short-term revenue and domestic prepaid customers were viewed as highly price-sensitive and quick to switch providers.
Marketing “5G” across a patchwork network
The complexity of modern mobile networks, combining different frequencies, technologies and rollout levels, made it hard even for specialists to assess consistent 5G quality. Operators marketed a broad spectrum of services as 5G, ranging from genuine high-speed connectivity to enhanced 4G branded as “5G Evolution” or “5G Ready.” DTAC used this grey area by selling 5G plans to customers with 4G-only devices, where data volumes and call allowances matched the offer but the headline speeds were technically unreachable.
When promises met everyday experience
The DTAC 5G controversy highlighted a wider issue in the telecom industry, where marketing routinely promoted speeds and coverage achievable mainly under ideal test conditions. Fine print and technical limitations often obscured real-world performance, and many customers did not actively measure data rates. For prepaid users, the lack of long-term contracts reduced their bargaining power, and complaints frequently stalled in customer service queues, with hotlines overloaded and online support via Line or Facebook responding with generic messages.
Calls for clearer information and tougher rules
Recommendations for affected users included checking device compatibility before buying a prepaid package, using the DTAC online tools where available, and comparing offers from different providers on the ground, as price gaps were small while performance differences could be substantial. Commentators argued that Thailand needed stronger competition and regulation in the mobile market after the True–DTAC merger, which critics said should never have been approved. They called for stricter advertising transparency, minimum speeds for all tariff categories and easier switching between operators to strengthen customer rights.
Business decisions behind the 5G icon
Thailand’s mobile infrastructure was described as among the most advanced in Southeast Asia, and the core issue was not a lack of towers or spectrum. Instead, it lay in deliberate business strategies that sidelined certain customer groups, particularly prepaid users who paid less than postpaid customers but still expected reliable service. When tourists spent 899 baht on a 30‑day package, they often received throttled connections, missing language options and limited support, affecting not only DTAC’s image but also Thailand’s reputation as a tech‑savvy destination.
Unequal access to the 5G revolution
The confusion surrounding DTAC’s prepaid 5G offerings was portrayed as a result of economic priorities in a highly concentrated market rather than a technical failure. The merger with True Move eased initial spectrum shortages but created new problems by reducing competition and pushing prepaid users – both tourists and locals – to the end of the priority list. The promised 5G revolution took place mainly for premium postpaid customers, while those relying on cheaper prepaid plans navigated slow connections and opaque conditions, with the 5G symbol on their screens often amounting to a marketing label without corresponding performance.