Speaking to reporters before departing Hong Kong on a Thai airways flight, he said he was a "little bit" concerned about his security, but he added he did not think his return would spark violence.
"I used to say when I was prime minister that there were attempts to assassinate me. Normally I would have some concerns but I hope that everyone is thinking of national reconciliation and they will prepare (security measures) for me well," he said.
Thaksin has spent most of his time in exile living in the UK, where he owns Manchester City football club.
His wife Pojaman, who returned to Thailand last month, also faces corruption and conflict of interest charges from when her husband was prime minister.
The charges were brought by the previous government installed by the Thai military after the 2006 coup.
Thaksin's return was secured by Thailand's newly-elected leader, Samak Sundaravej, whose People Power Party (PPP) is regarded as a proxy for Thaksin.
The PPP, comprising mostly of Thaksin allies, won nationwide elections in December and forms the core of Thailand's new six-party coalition government.
Thaksin himself has repeatedly said he has no plans to return to politics, although supporters and opponents both doubt his claims.
Senior officials from the PPP are expected to be at Bangkok airport to welcome Thaksin as he returns on Thursday – as are court officials who will present the corruption charges to him.
Chalerm Yoobambrung, the country's newly-appointed interior minister and a long-time Thaksin ally, said he will personally welcome the former prime minister with open arms.
"I will be there as the old friend ... who promised voters that if they chose the People Power Party we would bring Thaksin back with full honours."
Thaksin is being accompanied on his return by two Manchester City players who have said they plan to hold soccer clinics with Thai children and work out the national team.
Warning
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Thaksin, seen with his wife Pojaman, has lived
in exile since the 2006 coup [GALLO/GETTY] |
On Tuesday Samak Sundaravej, the Thai prime minister, warned activists not to take to the streets during Thaksin's return.
A spokesman for Samak quoted him as saying: "It's normal that he must defend himself in the court and my government will not interfere."
Thai officials have said that protesters could be charged with obstruction of justice if they try to prevent Thaksin from reporting to court.
Critics fear Thaksin's homecoming could plunge the country into another political crisis.
His opponents have threatened to mobilise protesters and stage demonstrations if the new government tries to intervene in the legal process against him.
Thaksin and his wife each face up to 13 years in jail over two corruption charges alleging she used her husband's political influence to buy prime Bangkok property from a government agency at about one third of its estimated value.
Thaksin denies any abuse of power.
The couple also face separate charges of making fraudulent filings with the Securities and Exchange Commission over the 2003 listing of a property company.
Following the coup, Thaksin's Thai Rak Thai [Thais Love Thais] party was disbanded for electoral fraud and more than 100 senior party officials including him were banned from politics for five years.